Problems with webdav - authentication constantly popping up

Nextcloud version (eg, 10.0.2): 11.0.2
Operating system and version (eg, Ubuntu 16.04): 16.04
Apache or nginx version (eg, Apache 2.4.25): 2.4.18 (Ubuntu)
PHP version (eg, 5.6): 7.0.15
Is this the first time you’ve seen this error?: has been there since beginning (September / Version 9)

Can you reliably replicate it? (If so, please outline steps): Yes, every time a user opens a file via network drive

The issue you are facing: When trying to open files on Nextcloud (Connected as network drive on windows) the user is constantly prompted with Windows Authentication prompt. Selecting “Save User Details” does nothing.

The output of your Nextcloud log in Admin > Logging: **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 public access to this resource., No ‘Authorization: Basic’ header found. Either the client didn’t send one, or the server is misconfigured, No ‘Authorization: Basic’ header found. Either the client didn’t send one, or the server is misconfigured

[internal function] Sabre\DAV\Auth\Plugin->beforeMethod(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))
/var/www/nextcloud/3rdparty/sabre/event/lib/EventEmitterTrait.php - line 105: call_user_func_array(Array, Array)
/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 466: Sabre\Event\EventEmitter->emit(‘beforeMethod’, Array)
/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 254: Sabre\DAV\Server->invokeMethod(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))
/var/www/nextcloud/apps/dav/lib/Server.php - line 227: Sabre\DAV\Server->exec()
/var/www/nextcloud/apps/dav/appinfo/v2/remote.php - line 30: OCA\DAV\Server->exec()
/var/www/nextcloud/remote.php - line 165: require_once(’/var/www/nextcl…’)
{main}**

Does noone have an idea about why this may be happening?

This might rather be a problem on the Windows side with the DAV integration.
What Windows version do you use? What steps did you perform on Windows to bind NC as network drive?

I haven’t done this myself yet, so I’m not sure of errors would be written into the Windows event logs, but maybe you can have a look at them, if you find some related entries. If so, what do they read?

Without knowing the requested details I would suggest to try to clear all the entries for the NC connection in the “Control Panel → All Control Panel Items → Credential Manager”. Meaning, remove every entry that is network drive/ NC related.
Afterwards connect and enter the credentials again and check “save login credentials” again.
I had issues in the past, where the credential manager caused problems and clearing the entries helped. Maybe this applies to you as well.

And maybe this thread helps you a little:

Did you try the ideas mentioned here?