You need to implement OAuth with Microsoft (or Google if using Gmail).
It was implemented in all supported versions 14-16, I wrote a blog article which should help.
Implementing OAuth with Outlook or Gmail in Odoo (openusersystems.com)

You need to get the 'microsoft_outlook' & updated 'fetchmail' module from the Odoo core files & install/update your installation. This is what cured the problem for me.

I also interested in solution