I have run into the 500 error myself a few times.
When logging in through Google.
I have been able to override the error, by hitting the refresh button and re-clicking the Google log in button.
It may take a few tries, but Its worked for me a few times now.
May be a flaky Router somewhere along the line.
Try getting in again with your Google address .
Doing the above. You may get lucky.
Re: Google login broken. How to recover templates?
I use private settings on my browser.
Set to delete all tracking data on exit.
I have run into the problem on fresh start of my browser.
With no cookies to start with.
That is not saying that Googles tracking cookies might not be part of the issue.
latest days I was running on error 500 on Google login, but only I reloaded the page and I could work normal, but today I could not to do anything due for the error 500 after login with Google account.
Maybe Google one more time changed some on OAuth and need to be updaated on SUSE Studio or maybe happening another thing.