Use your caps key to turn off the use of capitals. That is perhaps some of the hardest text in the world to read all in upper case.

I would guess that the transmission is affected by your antivirus program. Fundamentally Thunderbid does exactly the same thing to all messages when sending regardless of the recipient. So your observed behviour would indicate an external source of the issue.

You might try running Thunderbird is troubleshooting mode from the help menu to see if it is perhaps some addon or theme causing this particular thing. But on first impressions I would guess external to Thunderbird.

Hi Matt. Many thanks. Apologies regarding the caps lock. I found how to run "troubleshooting mode", which appears to disable all add-ons etc;t thanks for that also. However the same thing occured. A message comprising the one word "test", sent to myself, arrived virtually instantly as has been normal this past 30 years of my ownoinc computers. The same single word message, only to my wife.......is then very very slow to go. Likewise if I send it somebosy else instead. So it is only an email to myself that works normally. An email to any other one individual, (or more) is slow to send. And an email send to MY address (as in the first scanrio) but with even one added person, is immediately very slow again. I get a little "progress" bar just to send one word. My Broadband speed is fine. My computer is an I9 multi core very high spec, 3 months old , windows 11. If that gives you any further clue I' be very grateful indeed to solve this issue. Especially as you clearly know more than I do, and are telling me that the rule is that Thunderbird treates every recipient the same. Something therefore is very wrong here for that rule to be so clearly ignored. It is way beyond my skills or understanding. Thank you again for your response.

If you have a wired internet connection (no wifi in safe mode) try using your operating systems safe mode for the test. Instructions for each operating systems safe mode: Windows 10/11, Windows 8, Windows 7, OSX