the instance you are registered with decided to defederate with some instance
This might explain why I can't find communities which allegedly exist, or why I can't choose my home instance in the android app to log in.
It might. I'm not getting any error which clearly states the malfunction is due to defederation.
How does one achieve clarity? Is there a map, which shows which instance is (de)federated to which other instances?
Nice, thank you! There is only one defederated, the infamous lemmygrad.
Though I don't think this explains the issues I have. Maybe it's the overall load due to the reddit migration.