How to login Nextcloud with Windows WebDAV

Nextcloud version (eg, 10.0.2):12.0.0
Operating system and version (eg, Ubuntu 16.04):CentOS 7.3 and Plesk Onyx 17.0.17
Apache or nginx version (eg, Apache 2.4.25): 2.4.6
PHP version (eg, 5.6):7.1

Is this the first time you’ve seen this error?:
System Error 5 Access denied or Error 1244 Not certified

Can you reliably replicate it? (If so, please outline steps):
On comand prompt

  1. net use http(s)://mynextcloud.com/remote.php/dav/files/USERNAME/
  2. net use http(s)://mynextcloud.com/remote.php/dav/files/USERNAME/ /user:USERNAME PASSWORD
  3. net use http(s)://mynextcloud.com/remote.php/dav /user:USERNAME PASSWORD
  4. net use http(s)://mynextcloud.com/remote.php/dav
    I can’t connect at all with the methods of item 1 and item 4.

The issue you are facing:
All errors occurred in the above way. I can’t log in even by drive mapping with Windows Explorer.
I have time to connect with them on time. Basically I can hardly connect with them.

net use http(s)://mynextcloud.com/remote.php/webdav
I can connect (with high probability) this way.
Nextcloud officially announces “remote.php/dav/files/USERNAME/”.

I can connect with /webdav/ and can’t connect with /dav/.
What is the difference?

When I connect to nextcloud for the first time after starting Windows, connectivity at this time is very unstable. After coldstarting or rebooting the PC, I seem to need to delete the connection registration once.
*By Windows ribbon menu or net use /delete command.
Is there any improvement plan?

The output of your Nextcloud log in Admin > Logging:

Sabre\DAV\Exception\NotAuthenticated: HTTP/1.1 401 No public access to this resource., No ‘Authorization: Basic’ header found. Either the client didn’t send one, or the server is misconfigured, No ‘Authorization: Bearer’ header found. Either the client didn’t send one, or the server is mis-configured, No ‘Authorization: Basic’ header found. Either the client didn’t send one, or the server is misconfigured

or

Sabre\DAV\Exception\NotAuthenticated: HTTP/1.1 401 No ‘Authorization: Basic’ header found. Either the client didn’t send one, or the server is misconfigured, No ‘Authorization: Bearer’ header found. Either the client didn’t send one, or the server is mis-configured

or

Sabre\DAV\Exception\NotFound: HTTP/1.1 404 File with name USERNAME could not be located

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):

My config.php:

<?php $CONFIG = array ( 'instanceid' => 'XXXXX', 'passwordsalt' => 'XXXXX', 'secret' => 'XXXXXXXXXXXXXXXXXXXXXXXXX', 'trusted_domains' => array ( 0 => 'NEXTCLOUDDOMAIN.com', ), 'datadirectory' => '/var/www/vhosts/MYDOMAIN/nextcloud/data', 'overwrite.cli.url' => 'https://NEXTCLOUDDOMAIN.com', 'dbtype' => 'mysql', 'version' => '12.0.0.29', 'dbname' => 'NEXTCLOUD_DB', 'dbhost' => 'localhost:XXXX', 'dbport' => '', 'dbtableprefix' => 'oc_', 'dbuser' => 'SQL-USER-NAME', 'dbpassword' => 'SQLPASSWORD', 'installed' => true, 'logtimezone' => 'UTC', 'memcache.local' => '\\OC\\Memcache\\APCu', 'mail_smtpmode' => 'smtp', 'mail_smtpauthtype' => 'LOGIN', 'mail_smtpsecure' => 'ssl', 'mail_from_address' => 'MAILNAME', 'mail_domain' => 'MAILDOMAIN', 'mail_smtpauth' => 1, 'mail_smtphost' => 'SMTPDOMAIN', 'mail_smtpport' => '465', 'mail_smtpname' => 'XXXX@MYDOMAIN', 'mail_smtppassword' => 'MAILPASSWORD', 'loglevel' => 0, 'logfile' => './nextcloud.log', );

I tried the following items.
This seems not to improve.

SetEnvIf Authorization “(.*)” HTTP_AUTHORIZATION=$1