@null @analytodon I use arc for macOS. I've tried with Firefox and it works. Maybe some extension (arc uses Chromium) causes the problem. I will do some research in the evening.
@null @analytodon How i suspected. The problem is caused by AdBlock extension. If I deactive it in Arc it starts working.
Vielen Dank für Unterstützung :-)
@aquarius061 @analytodon interesting. Thanks for the update. I wonder how the ad blocker would cause this error, though. Maybe I’ll investigate it further at some point.

@null
I get this issue with both Firefox and Chrome on Android. I've tried in private browsing mode as well. Haven't tried on a desktop yet.
@aquarius061 @analytodon

Update: It seems like I can successfully use the login page with Vivaldi. Doesn't make sense to me, but I haven't dived into devtools yet

@h3mmy @null @analytodon Yes it is really strange. Maybe some headers are added/removed.
@aquarius061 @h3mmy @analytodon I suspect it’s got something to do with server-side rendered content not being the same as client-side, leading to a mismatch which ultimately leads to this error. I thought I’ve taken every precaution to avoid this but it seems there’s more in some special cases. Unfortunately, I’m very busy again with other stuff and haven’t been able to properly look into it yet.