I may be mistaken, but OAuth2.0 is definitely supported my Office365. In fact, as far as I know, it is the ONLY thing supported by Office365.

The issue in the referenced post was due to trying to use an External Application to connect a different account than was authenticated.

Is that what you're trying to do?

Is it possible that POP or IMAP is blocked in your tenant for the account you are trying to use?  Hope you can get it figure out. 

Thats Right, at the moment I'm trying to use an external Application to connect a different account but is already add on Azure

Then as the article states, at the moment, this is unsupported. You need to set up an External Application for each account you’re trying to connect. You don’t need to create a new Azure app for each account though (because it’s Acumatica’s limitation, not Microsoft’s). You can use the same Client ID and Client Secret for each External Application. 

I understand, I've already tried to create a new Azure app as well as create multiple new Client secret key clients, but it still reflects

That’s not necessary. You need multiple Acumatica External Applications. Each Email Account needs to be tied to an External Application which is signed in with the email address being used for the Email Account:

I would double check in you Admin portal in MS365 for the account you are trying to use that you have IMAP allowed. If you have a conditional access setup in Entra ID (Azure AD) that blocks IMAP you would also need to make an exception for the account. 

MS has also been having Exchange issues over weekend and into this week which may or may be causing this issue.  You may want to wait for this to be resolved before troubleshooting more. 

*You will also need to “SIGN IN” again in Email Accounts after making any changes in Manage email apps