Outlook 2016 not sending mail

I have a workstation that has Outlook 2016 loaded, the user has access to two mailboxes, each on a separate domain but running off the same Exchange 2013 server.
Both mailboxes can receive mail just fine, one can send, the other can't. Logging into OWA shows that the problematic mailbox does work as it can send and receive mail without issues. I have recreated the ost file, repaired Office and am still not able to get it to work.

Error attached.
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Ashish SinghData ScientistCommented:

There can be many reasons behind this issue. Please check below link to fix your Outlook issue:


Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
Jackie ManIT ManagerCommented:
It is very likely to be an SSL cert problem.

Are you using UCC (SAN) cert on the said  Exchange 2013 server?
DJMohrAuthor Commented:
Recreating all outlook profiles solved the issue.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.