When heading to community.pandora.com after not having visited for a day or so, a huge red banner says Authentication Failed along with a bulleted list of what might be going on. From that page, if I click Sign In, I am instantly logged in, revealing that I still had an active session. I think something is wrong with the https://www.pandora.com/account/community-redirect page in my history.
I was having this problem, too (15 October 2023) and found the issue was that I wasn't properly registered with the Creators community.
As I didn't know what I didn't know, the error message seemed illogical and baffling. Luckily, I stumbled upon the magic button to join the creators community, and it's all sorted now.