Login failing after some time

Hello i got a problem with my home assistant appliance
I am running hassio on an RPI3 and sometimes after trying to login
the followin error appears:

Error: Something went wrong

If I look in the development console of my browser it says
Error submitting step SyntaxError: JSON.parse: unexpected non-whitespace character after JSON data at line 1 column 5 of the JSON data authorize.863496ae.js:2260:2824

The only thing thats helping after that is deleting the auth files and creating a new user

This happenes randomely every few times

I dont know where this issue is coming from…
Maybe its a bug in the newest home assistant version?

I hope that this bug gets resolved soon, or if it’s a misconfiguration maybe someone can help me out?

thx

greetings Pascal.

Okay maybe i just resolved this by myself.

Apparently the login works with a newer Firefox version.
So the problem could be that i am using waterfox which is based on an older firefox version.
This bug does not seem to occur on an up to date firefox version