Unable to send emails using Outlook 376

Hello Andre,
We will help you to resolve the issue.
Please disable AVG temporarily as mentioned here and verify the status.
Keep us updated on the progress.

Since I purchased and installed AVG Internet Protection, I am unable to send emails.  Incoming emails is working fine.

Case closed, thanks.
We appreciate your efforts.

Are you able to send the email after disabling the AVG?

I still cannot send emails. The problem started when AVG VPN Secure installed.

Hello Andre,
We will help you to resolve the issue.
Please disable AVG temporarily as mentioned here and verify the status.
Keep us updated on the progress.

Thank you for the clarification, Andre.
We request you to follow the steps as mentioned under this article and see if it helps.
Keep us posted.