Can't launch session

After today's update I can't get into a session from UEFN. It just says "preparing" forever. No errors, nothing pops up, log is empty. Tried launching on PS5 and PC. Closed everything, relaunched everything, verified files. Nothing, just prepares endlessly. I was on like 10 hours ago and haven't changed anything yet.

Edit: I finally got an error. It says:

We failed the cook request for the server. Invalid_results