Hi. I have the same issue. My WebDAV does not work anymore since a few days, with mention “Hors Ligne” (Offline), which is not true. The screen of the setup which says it cannot find the server. On the screenshot the server adress is truncated, but the full value is : 1892885.connect.kdrive.infomaniak.com (and I tried aswell with https:// in front of it).
Not sure if this was for me, I guess not because it was marked as loved by someone else and marked as solution. I might need to open another issue, for me it is not resolved and it’s not linked to the folder.