Unable to complete Instance Battles

So I read the sticky that said that the error "The instance server has encountered an error [Error Code 90000]" was fixed, and to their credit I'm sure it is. However it has been replaced by a "Connection with the server was lost. [Error Code 90000]". At the end of the day, is this not -exactly- the same error?

Every instance battle I've been in has produced this error, to the point where I'm unable to progress with anything because I can't stay in the instance long enough to finish it. Sometimes I get kicked right at the start, others it'll work for a few minutes before kicking me.