When I try to Import from Trello I get the error below. This is due to trello automatically revoking access after one hour. This error should be handled and ui should present a reauthentication dialog.
GuzzleHttp\Exception\ClientException: Client error: GET https://api.trello.com/1/boards/***... resulted in a 401 Unauthorized response: expired token in
Hello @yves, welcome to the community!
When does the error happen? When you have already started the process of importing and then leave the screen idle?
If you have a minute you can also write back via our chat support, it is definitely a much better and faster way of reporting bugs as we have almost 24/7 support available there. 
It’s the chat bubble in the lower right corner when you’re in the tool.
That’s correct. I have started one import - worked fine. Then left the screen idle (30min+). Then the following imports fail (as trello revoked the access in the meantime).
Hi @yves, thanks for clarifying.
I will note it down for the team so we can improve this in the future.
Cheers!