Thanks for reporting this! I've looked into the issue.

To try to standardize how communities are loaded, the app always uses the fully qualified name when loading communities. That is it loads communities using the name [community_name]@[instance].

This works for most instances but for some reason burggit.moe appears to be blocking any queries to [community_name]@burggit.moe. This might be a misconfiguration from the admins of burggit.moe? It's possible they have configured their instance to be white list only (eg. only instances they whitelist will be supported) and did not whitelist their own instance? I'm just guessing here.

I can add a fix in the next update to whitelist burggit.moe so fully qualified names will not be used on that instance.