Not sure how to reproduce this; but maybe the description will help... Just finished upgrading my Internet link which resulted in a temporary network outage during the switchover. Just before the link went down, CM got a certificate change from a server and posted the dialog. I didn't notice it when the old link went down. Eventually got the new link up, noticed the dialog & clicked Accept. However, CM was now hung on this server. I suspect the problem occurred because the IP address changed while the dialog was up and CM was waiting for a response from me. By the time I accepted the new certificate, poor CM had outstanding network activity, but the system's IP address was changed and Stop All was ineffective. Killed & restarted CM to resolve.