I'm afraid I'm missing the obvious here - but:
I created my cloud account in June 2010 (ossi1967.status.net). Worked like a charm. No complaints.
After a while, I realized I could no longer write to the !groups from identi.ca I had subscribed to. Then, I could no longer reply to dents from users (from identi.ca) I had subscribed to. (I don't get an error. My messages just never appear.)
Following a stroke of genius, I deleted all group-subscriptions. Trying to re-subscribe now results in the infamous error
> 500 Failed joining remote group.
I did search around here and found some related posts (incl. fixes), but they seem to be useful only for people who run their own instances of statusnet - not for the lazy like me who rely on the hosted service.
Not being able to communicate with other users/groups makes status.net a lonely experience. (I still recieve dents from the people I subscribed to, though.)
What is it I'm missing?