I send a mail to some 80 recipients. The mail is stuck in the local outbox without further notice. 'Send outbox' returns same result - nothing happens, no notice. Akonadi Server restarted - no change. When I copy the mail to the 'Drafts' folder I'm able to send it from the Web-Frontend of the EMail service. I then get some bounces (mailbox unavailable etc), I assume this is checked during the SMTP-Send, but the result is not displayed. When I remember this right, that worked in earlier version... Reproducible: Sometimes Steps to Reproduce: 1. see above 2. 3.
So...tested on KMail 4.14.6: Sending to 82 recipients works, to 83 fails w/o notice! Laurent, can you maybe create your testcase if you just send to 123@outlook.com 234@outlook.com etc, in case there are less recipients available?
KMail 4.14.9 - same issue :-(
KMail 4.14.10 as well :-(
By the way, I cross-checked with a different mailer - it is not an issue of the provider (blocking large number of recipients), it is really a KMail Problem...
Tested against KMail 5.5.3 (openSUSE Tumbleweed) - bug seems to be removed. Close as working