Sorry for this second post.
I should add that the same behavior happens whenever the network connection is interrupted for whatever reason. Evolution detects the interruption, then when the connection comes back it hangs trying to connect to the server. This does not happen if I just click on the button in the left bottom of the Evolution window to put it offline (with the network connection still online): when I put evolution online again it works. So the issue is related to evolution loosing the connection and not with evolution going offline. And it is not related to suspension but to loosing the connection.
Sorry for this second post.
I should add that the same behavior happens whenever the network connection is interrupted for whatever reason. Evolution detects the interruption, then when the connection comes back it hangs trying to connect to the server. This does not happen if I just click on the button in the left bottom of the Evolution window to put it offline (with the network connection still online): when I put evolution online again it works. So the issue is related to evolution loosing the connection and not with evolution going offline. And it is not related to suspension but to loosing the connection.