Since I posted this problem, I did a apt-get update for other reasons and the tls problem seems to have disappeared. (So far anyhow)
Tom Fowle WA6IVG Using mutt 1.5.23 with Debian 8 jessie. I am getting the following problem while reading messages. approximately: "The TLS socket was improperly terminated. can not copy messages." This appears on the screen for only just long enough for my screen reader to grab it but dissappears before I can copy or check it.. I then have the usual top line menu and a blank screen. Being simplistic by nature I just exit mutt and restart but all messages which have been marked for deletion remain in the inbox and unless i have kept carefull track of the last read message number before the TLS error I have to trundle through all the previously read messages till I find the first unmarked message. This problem is becomming more frequent, often two occurrences in a hundred message session. Before I get into just updating mutt and debian as the most likely resolutions, would like to know if this is a known problem and whether the mutt or "OS" updates are more likely to fix it. PLS don't yell at me for not being up to date, I hate updating. So now I'm paying the price. TNX Tom Fowle WA6IVG