Sending multiple emails from Outbox
I have recently installed version 146.0.1 on a new computer, was using 115.10 before. I regularly put about 50 emails in my outbox using the mail merge add on and then send them in one go. I have done this very successfully for a long time using my Fastmail email account. Now after sending about 10 of the emails, Thunderbird hangs and I have to restart it to send the next 10. If I send them via my Gmail account it still works fine. I am trying to understand if this is a Fastmail or Thunderbird issue. I would have liked to try it on my new computer but with version 115.10 but cannot do this as it seems that the Profile is different.
Any advice gratefully received.
Thanks Bob