The imaplib.IMAP4.error: AUTHENTICATE failed Error occured because one point in the documentation is not that clear.
When setting up the the Service Principal via Powershell you need to enter the App-ID and an Object-ID. Many people will think, it is the Object-ID you see on the overview page of the registered App, but its not!
At this point you need the Object-ID from "Azure Active Directory -> Enterprise Applications --> Your-App --> Object-ID"
New-ServicePrincipal -AppId <APPLICATION_ID> -ServiceId <OBJECT_ID> [-Organization <ORGANIZATION_ID>]
Microsoft says:
The OBJECT_ID is the Object ID from the Overview page of the
Enterprise Application node (Azure Portal) for the application
registration. It is not the Object ID from the Overview of the App
Registrations node. Using the incorrect Object ID will cause an
authentication failure.
Ofcourse you need to take care for the API-permissions and the other stuff, but this was for me the point.
So lets go trough it again, like it is explained on the documentation page.
Authenticate an IMAP, POP or SMTP connection using OAuth
Register the Application in your Tenant
Setup a Client-Key for the application
Setup the API permissions, select the APIs my organization uses tab and search for "Office 365 Exchange Online" -> Application permissions -> Choose IMAP and IMAP.AccessAsApp
Setup the Service Principal and full access for your Application on the mailbox
Check if IMAP is activated for the mailbox
Thats the code I use to test it:
import imaplib
import msal
import pprint
conf = {
"authority": "https://login.microsoftonline.com/XXXXyourtenantIDXXXXX",
"client_id": "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXXX", #AppID
"scope": ['https://outlook.office365.com/.default'],
"secret": "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX", #Key-Value
*(Réponse tronquée)*
