Commented Unassigned: WebDav sync stopped working [389]

I've been using KP2A for a while, storing my password file on a webdav server. At one point, maybe a couple months ago, KP2A started complaining about ConnectFailures and I have not been able to sync since. On the web server, there's no sign of any connection attempts. However, if I open the same URL from the same device from a browser, it opens w/o any problems.

I tried storing the password file on under a different URL, no change. Tried uninstalling and reinstalling KP2A, no change. I have no idea what's going on.

I don't really know what information to provide. The device in question is an S4 mini. Logcat shows the following:

D/KP2A (32505): Exception: System.Net.WebException: Error: ConnectFailure (Connection refused) ---> System.Net.Sockets.SocketException: Connection refused
D/KP2A (32505): at System.Net.Sockets.Socket.Connect (System.Net.EndPoint remoteEP) [0x00000] in <filename unknown>:0
D/KP2A (32505): at System.Net.WebConnection.Connect (System.Net.HttpWebRequest request) [0x00000] in <filename unknown>:0
D/KP2A (32505): --- End of inner exception stack trace ---
D/KP2A (32505): at System.Net.HttpWebRequest.EndGetResponse (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0
D/KP2A (32505): at System.Net.HttpWebRequest.GetResponse () [0x00000] in <filename unknown>:0
D/KP2A (32505): at System.Net.WebClient.GetWebResponse (System.Net.WebRequest request) [0x00000] in <filename unknown>:0
D/KP2A (32505): at System.Net.WebClient.OpenRead (System.Uri address) [0x00000] in <filename unknown>:0
D/KP2A (32505): OnFinish message: Hiba történt: Error: ConnectFailure (Connection refused)

Any idea?
Comments: Same Problem here, I don't even get a Stacktrace in my Logcat, nothing. Solid Explorer for example works, so its not a erver problem