API is disconnected when user leaves a project- even though API is still running

Hi there, 

A customer of ours has reported an urgent issue: when they close Trados and open it again, they must re-connect to the API, even though the connection is still live.

They see the following messages.

First, when they open the project again they get this:

And when they open Project Settings while in the project they get this:

All the while, the API is still running on our side. 

Any help with this issue is greatly appreciated.

Best

Louise