They did the same for me: I was - like the author - vague here, instead of "10/10 perfect score" and thus rejected pretty soon without any further information.
This is one of the long time running instances shutting down, linking to the primary nitter author saying it's the end for all instances eventually. And providing insights from the status page.
If they don't get new guest accounts, they're all going to shut down withing 30 days. It's just left over accounts and caches giving you the impression everything is fine.
Don't forget the rolling DoS herds of scrapers having no more ways to do stuff on their own, which are now trying to use the remaining instances - killing even more.