Support intro
Sorry to hear you’re facing problems 
help.nextcloud.com is for home/non-enterprise users. If you’re running a business, paid support can be accessed via portal.nextcloud.com where we can ensure your business keeps running smoothly.
In order to help you as quickly as possible, before clicking Create Topic please provide as much of the below as you can. Feel free to use a pastebin service for logs, otherwise either indent short log examples with four spaces:
example
Or for longer, use three backticks above and below the code snippet:
longer
example
here
Some or all of the below information will be requested if it isn’t supplied; for fastest response please provide as much as you can 
Nextcloud version (eg, 20.0.5): 25.0.5
Operating system and version (eg, Ubuntu 20.04): Ubuntu 18.04.6 LTS
Apache or nginx version (eg, Apache 2.4.25): Apache/2.4.54
PHP version (eg, 7.4): 8.1.12
The issue you are facing:
Files UI do not load properly, when image or pdf is clicked instead of opening in the web it begins to download to disk.
Is this the first time you’ve seen this error? (Y/N): Yes
Steps to replicate it:
The output of your Apache/nginx/system log in /var/log/____:
# cat /var/log/apache2/error.log
[Sun Nov 06 06:25:04.212341 2022] [http2:warn] [pid 1260] AH10034: The mpm module (prefork.c) is not supported by mod_http2. The mpm determines how things are processed in your server. HTTP/2 has more demands in this regard and the currently selected mpm will just not do. This is an advisory warning. Your server will continue to work, but the HTTP/2 protocol will be inactive.
[Sun Nov 06 06:25:04.310071 2022] [mpm_prefork:notice] [pid 1260] AH00163: Apache/2.4.54 (Ubuntu) OpenSSL/1.1.1g configured -- resuming normal operations
[Sun Nov 06 06:25:04.310125 2022] [core:notice] [pid 1260] AH00094: Command line: '/usr/sbin/apache2'
[Sun Nov 06 13:17:24.508456 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 13:17:25.513282 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 14:26:44.241991 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 14:26:45.243954 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 14:26:46.245562 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 17:36:33.974998 2022] [proxy_fcgi:error] [pid 7013] [client 100.198.105.13:60498] AH01071: Got error 'Primary script unknown', referer: http://mydomain.com/wp-login.php
[Sun Nov 06 21:33:18.445167 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:33:45.509820 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:33:46.511215 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:34:02.531393 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:34:45.627978 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:34:46.629322 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:34:50.634205 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:35:45.739473 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:35:46.740974 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:35:50.746060 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:36:51.874290 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:36:52.875889 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:36:56.880888 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:36:57.882661 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:37:47.986615 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:38:04.016989 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:38:48.073688 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:39:06.114110 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:39:50.468902 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:39:56.479728 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:39:57.481133 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:39:58.482748 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:40:00.484874 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:40:18.508293 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:40:23.517584 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:40:47.565192 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:40:51.570202 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:41:27.606831 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:42:07.661086 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:42:08.662945 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:42:09.664921 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:42:10.666394 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:42:11.667950 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:43:06.783247 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:44:06.848308 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:44:07.850296 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:44:08.851925 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:44:09.852784 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:44:10.853607 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:44:11.855185 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:44:45.989011 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:44:46.989510 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:44:47.990758 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:44:51.997254 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:45:55.080255 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:47:06.164244 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:47:07.165876 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:47:46.243149 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:48:06.266262 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:48:07.267858 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:48:08.269157 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:48:44.387764 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:48:45.389542 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:48:46.392237 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:48:49.397516 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:48:50.399256 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:49:46.482361 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:49:47.484020 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:49:54.500524 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:50:47.563845 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:51:53.636284 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:52:47.725145 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:52:52.729703 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:53:07.744549 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:53:28.796479 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:53:29.798342 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:53:35.806138 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:53:47.848392 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:53:48.850099 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:54:11.880509 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:54:12.882303 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:54:13.883992 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:54:14.885583 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:54:15.887045 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:54:16.888536 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:54:53.973937 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:55:49.066104 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:55:54.083737 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:55:58.088835 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:56:48.181112 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:56:53.187132 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:56:57.192331 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:57:50.277144 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:58:17.450359 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:58:52.904419 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:58:53.906624 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 21:59:46.971385 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:00:46.071554 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:00:47.072878 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:00:51.077713 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:01:47.190023 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:01:48.191553 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:02:02.208197 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:02:07.215516 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:02:46.281062 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:02:54.289454 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:04:08.379114 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:04:09.381046 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:04:10.382128 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:04:11.383571 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:04:50.462914 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:05:46.539941 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:06:53.619516 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:07:45.715323 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:07:46.716803 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:07:50.721964 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:08:45.803553 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:08:53.814572 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:09:02.823108 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
[Sun Nov 06 22:09:45.903426 2022] [core:warn] [pid 1260] (101)Network is unreachable: AH00056: connect to listener on [::]:80
Don’t see any error in the nextcloud.log
But I spotted something in browser console.
doesnt get fixed even after updating the nextcloud to newer latest version either.
Nextcloud is behind haproxy.
HA-Proxy version 2.2.3-2 2020/09/09
nexcloud/config/config.php
<?php
$CONFIG = array (
'instanceid' => 'oce3rsysxqpd',
'memcache.local' => '\\OC\\Memcache\\Redis',
'filelocking.enabled' => 'true',
'memcache.distributed' => '\\OC\\Memcache\\Redis',
'memcache.locking' => '\\OC\\Memcache\\Redis',
'redis' =>
array (
'host' => '192.168.1.23',
'port' => 6379,
'timeout' => 3,
'password' => '',
'dbindex' => 0,
),
'trusted_domains' =>
array (
0 => '192.168.1.23',
1 => 'mywebsite.com',
2 => 'home.local',
3 => '100.187.1181.90',
4 => 'my.website.com',
),
'trusted_proxies' =>
array (
0 => '198.168.1.23',
),
'has_internet_connection' => true,
'connectivity_check_domains' =>
array (
0 => 'mywebsite.com',
1 => 'my.website.com',
2 => '192.168.1.23',
),
'logfilemode' => 416,
'loglevel' => 2,
'loglevel_frontend' => 2,
'syslog_tag' => 'Nextcloud',
'syslog_tag_audit' => 'Nextcloud',
'logfile' => '/var/log/nextcloud/nextcloud.log',
'datadirectory' => '/mnt/storage/data',
'dbtype' => 'mysql',
'version' => '25.0.1.1',
'overwrite.cli.url' => 'https://mywebsite.com/nextcloud',
'overwriteprotocol' => 'https',
'dbname' => 'nextcloud',
'dbhost' => '192.168.1.11:3306',
'dbport' => '',
'dbtableprefix' => 'oc_',
'dbuser' => 'dbuser',
'dbpassword' => 'secret!',
'installed' => true,
'session_lifetime' => 86400,
'session_keepalive' => true,
'has_rebuilt_cache' => true,
'updater.release.channel' => 'stable',
'maintenance' => false,
'mysql.utf8mb4' => true,
'theme' => '',
);