Sorry to hear you’re facing problems 
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In order to help you as quickly as possible, before clicking Create Topic please provide as much of the following as you can (you can cut and paste this into your topic):
Nextcloud version (eg, 10.0.2): 12.0.3
Operating system and version (eg, Ubuntu 16.04): Ubuntu 16.04.3
Apache or nginx version (eg, Apache 2.4.25): 2.4.18
PHP version (eg, 5.6): 7.0.22
Is this the first time you’ve seen this error?: yes
Can you reliably replicate it? (If so, please outline steps): yes
Just use Microsft Edge for uploading file to Nextcloud server.
I tired with:
Win10 (Creators Fall Update 1709, build 16299.19) and MS Edge 41.16299.15.0 (EdgeHTML 16.16299)
Win10 (1703, build15063.726) and MS Edge 40.15063.674.0 (EdgeHTML 15.15063)
The issue you are facing:
The progress bar during file upload is not shown.
In other web browsers e.g. FireFox, Chrome, IE 11 it’s working fine.
The output of your Nextcloud log in Admin > Logging:
nothing interesting there
The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):
<?php
$CONFIG = array (
'passwordsalt' => '',
'secret' => '',
'trusted_domains' =>
array (
0 => 'localhost',,
),
'datadirectory' => '/var/ncdata',
'overwrite.cli.url' => 'https://nextcloud/',
'dbtype' => 'mysql',
'version' => '12.0.3.3',
'dbname' => 'nextcloud_db',
'dbhost' => 'localhost',
'dbport' => '',
'dbtableprefix' => 'oc_',
'mysql.utf8mb4' => true,
'dbuser' => 'oc_ncadmin',
'dbpassword' => 'dbpassword',
'installed' => true,
'instanceid' => 'instancepassword',
'maintenance' => false,
'mail_smtpmode' => 'smtp',
'log_rotate_size' => '10485760',
'memcache.local' => '\\OC\\Memcache\\Redis',
'filelocking.enabled' => true,
'memcache.distributed' => '\\OC\\Memcache\\Redis',
'memcache.locking' => '\\OC\\Memcache\\Redis',
'redis' =>
array (
'host' => '/var/run/redis/redis.sock',
'port' => 0,
'timeout' => 0,
'dbindex' => 0,
'password' => 'password',
),
'htaccess.RewriteBase' => '/',
'loglevel' => '2',
'log_type' => 'file',
'logfile' => '/var/ncdata/nextcloud.log',
'logtimezone' => 'Europe/Prague',
'mail_from_address' => 'share',
'mail_smtpauthtype' => 'LOGIN',
'mail_domain' => 'ourdomain.com',
'mail_smtphost' => 'our.mail.server',
'mail_smtpport' => '25',
'knowledgebaseenabled' => false,
'skeletondirectory' => '/var/www/nextcloud/core/skeleton_1',
'updater.release.channel' => 'stable',
'default_language' => 'en',
'force_language' => 'en',
);
The output of your Apache/nginx/system log in /var/log/____:
nothing interesting there
Remember, this information may be requested if it isn’t supplied; for fastest response please provide as much as you can 
Feel free to use a pastebin service, otherwise log files can be indented with 4 spaces on each line to present them in a friendlier way on the forum.