Avast (free), Outlook 2016 and Gmail

[Clientdunet]

My config:
Windows 10 pro 64 bit
Outlook 2016 64 bit
Avast Free 20.8.2432 (version 20.8.5684.604)

For a few days I have to deactivate temporarily Avast to be able to use my Gmail mailbox in Outlook2016.
This only happens with Gmail, I have other emails form other providers, in outlook that work fine
I tried to change the SMTP port on Gmail account but it doesn't work.
Any suggestions?
Thank you

[rocksteady]

See other post where people have repoted issues with Gmail using Thunderbird email client. Don't know if that will give you a clue.
https://forum.avast.com/index.php?topic=239466.msg1567072#msg1567072