Apparently from Microsoft: https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/deprecation-of-basic-authentication-exchange-online

Asked me to read (Simplified Chinese, translate to English through Google Translate): https://mp.weixin.qq.com/s/Uwd6AkL1_KPoJ8XoXBMU-Q

Link to Azure: portal.azure.cn/

Found a Sage 300 document mentioning about this. Followed: support1.na.sage.com/.../viewdocument.do

Created AD user for emailing.

Set the OAUTH2 secret.

Adjusted tenant details.

Still got error.

Using this as well from Google Search, still got issue: community.blueprism.com/.../microsoft-graph-api-setup-with-delegated-permissions

Were you ever able to overcome this hurdle? 

We're between patches v11 -> v12.18.4.2 and due to begin migratory activities in the near future. 

Unfortunately no, my dear.

I am using this method as a compromise:  RE: Using Outlook wrt New email client for Sage X3 workflow notifications post. 

Refer to Andy S confirmed reply at the comment chain.

Set Notification Server to type: SMTP.