I updated nextcloud today to 18.0.4. Since that update I have massive problems synchronizing my data with any devices. This does not impact the android or iOS clients but I have ActiveSync installed on my server through the open source project z-push. I use that protocol to push any change (contact, calendar or mail) between clients and server. With 18.0.3 everything was working fine but with 18.0.4 I suddenly get the error message
BackendCalDAV->Logon(): User 'MyUser' is not authenticated on CalDAV 'https://localhost:443/nextcloud/remote.php/dav/calendars/MyUser/'
That error message makes absolutely no sense as I use the same credentials to log onto the nextcloud web front end which works perfectly fine. I tested all three backends that I configured with these credentials, imap, caldav, carddav. I do not even know where to look anymore.
Can anybody help with this issue?