server
The Aqara home app allows you to add the Aqara hub, but in order to get the complete
experience from the hub, you should use the server relevant to the region your hub belongs to.
So, if you have a Chinese hub, the hub will work as intended when signed into the Aqara home app, with the server set to ‘Chinese’.
If you have the US or European hub, then the US or EU servers are the best ones to use.