Files won't open via WebDAV anymore

[rucksman]

I updated our Nextcloud instance to 13.0.7. Since then opening files via WebDAV does not work anymore. If I try to open an Excel file for example via double click, Excel opens but does not load the file. For about 30 seconds only the blue Windows 10 circle is spinning, then it stops and Excel has not loaded anything. In the right top corner I see a yellow exclamation mark next to my nextcloud-account name. On very rare occasions after another minute or so a new Excel instance starts and the file is loaded, but this happens very rarely.

Opening a file via the website is no problem, Excel starts and loads the file immediately. But savinf changes then via WebDAV takes ages or is not possible at all.

Nothing on the server changed, I only updated Nextcloud to 13.0.7.

[nextcloud-bot]

GitMate.io thinks possibly related issues are #9790 (shared file is not shared anymore when opened and saved via WebDAV Network connection), #3738 (Webdav), #5996 (Do not get data via webdav), #10367 (Files header is not fixed anymore), and #3628 (Cannot upload files using webdav extension.).

[rucksman]

Problem was that for some reason the login for one user did not work anymore. I was not aware of this "Brute-Force-Attempt" function, because there is nothing to see in the backend. So in the end I fixed it by deleting the entries from the database.