After upgrading to 4.9.1.80 - There was an error processing the request. Please try again later.

[WtfJoke 2]

So I upgraded from 4.8.11.0 to 4.9.1.80.

Now each click on the web ui will do nothing or result in an error popup "There was an error processing the request. Please try again later.".
I've tried already downgrading to 4.8.11.0, but still the same error is happening now.

In the logs there are some erros, but im not sure if they are related. I hope you can help me.

embyservererrors.txt

[Luke 42077]

HI, this is only a 25 second log file here. I don't see any web app activity. Please try clearing browsing data and see if that helps.

If it doesn't help, then please attach the complete emby server log and indicate the time the problem occurred.. Thanks.

[WtfJoke 2]

I'm not sure what exactly helped, but after I tested it in a private tab it worked again on the non private tab as well.... Upgrade worked afterwards as well. 

Thank you for the fast response and your help anyways!