I've been having outgoing email issues and have been working with the postmaster to try and fix but not solved yet.
It started a couple of weeks back - can receive but not send email on Outlook 2016.
Then I had issues on my Iphone.
Changing outgoing ports seems to help sometimes (25 and 587) but I've reinstalled Outlook, fully turned off Norton, tried different wifi/4G connections but I'm still getting continual issues sending.
I'll have periods of 2-3 hours where it all works fine but then suddenly emails will sit in outbox and I'll get an
With trial and error sometimes changing to outgoing port from 25 to 587 (or vice versa) sometimes works, other times no change.
Iphone has had similar issues on and off, but this is always set to port 587
I'll get in touch with our system administrator/postmaster as well.
Have you tried or are you able to send out emails using webmail or different email clients apart from outlook?
Thanks for those info, can you PM to me the email address or addresses in outlook you are having issues with and also the subject line to your email to postmaster so I can check with them?