First check with your mail provider which authentication method is set.
Xentral can only use the classic (old) authentication and not the new OAUTH. This must be changed directly at Office365.
Check again if the connection is done as described in this helpdesk article: Set up default e-mail.
Use the following settings for Office 365 email accounts:
- Username: firstname.lastname@example.org
- Password: your password
- Outgoing mail server: smtp.office365.com
- Port: 587
- Encryption: TLS
- The sender's e-mail address must match the e-mail address stored under user name
- Sending e-mails from external sources may have to be allowed in the Outlook settings first
- No firewall may block the sending or receiving of the mails
- It may be that sending via SMTP is not allowed in the Outlook license and a higher license is needed for it
You can find more information in our manual: