Does not happen all the time. Many time works no problems. When having problems seems to be that way for a while not just one email. Just did an email and wheel was spinning and trying to send. "Can't log on to server" I believe is what comes up. Hit cancel, went into sent file to see if went thru(sometimes it does when it says it didn't send) Not in sent file, started new email and redid it and it sent fine??? Have been told looks like thunderbird issue and not Provider? My sent file is small. Thought this might be contributing so deleted most of old that I did not move in to client folders.