Content Comparison

cmsbs.mail.imap.server                = outlook.office365.com
cmsbs.mail.imap.port                  = 993
cmsbs.mail.imap.ssl                   = true
cmsbs.mail.imap.user                  = <mailbox_name>
cmsbs.mail.imap.authenticationMethod  = oauth2
cmsbs.mail.imap.oauth2.accessTokenUri = https://login.microsoftonline.com/<tenant_id>/oauth2/v2.0/token
cmsbs.mail.imap.oauth2.clientId       = <client_id>
cmsbs.mail.imap.oauth2.clientSecret   = <client_secret>
cmsbs.mail.imap.oauth2.scope          = https://outlook.office.com/.default
cmsbs.mail.imap.oauth2.grantType      = client_credentials
cmsbs.mail.imap.oauth2.debug          = true

Please keep mind that the Client secret you created earlier has an expiration date.

Your will have to create a new one and change your UM configuration accordingly at some point in the feature.