Frequently Asked Questions
After switching email accounts to Microsoft 365, many users encounter issues when trying to send emails using third-party apps like Mail Designer 365. The reason: Many Microsoft 365 plans no longer include traditional SMTP access or only allow it through complex OAuth2 authentication methods.
The classic login using just a username and password (for SMTP, IMAP, or POP3) is often blocked or disabled by default.
What does this mean for SMTP in Mail Designer 365?
Mail Designer 365 requires a working SMTP connection to send emails via SMTP. If that connection is no longer available after the migration, the login to the mail server will fail – even if the password is correct.
Solution:
Use the built-in Mail Designer 365 sending service instead, either with Direct Send or Campaign Sending. This allows you to send your newsletters reliably, without depending on your provider’s SMTP limitations.
Additional benefits:
With custom domain authentication (DKIM, SPF, and DMARC), you are set up for the future. Mail Designer 365’s sending service uses modern delivery technology to help ensure your emails reach the inbox – not the spam folder.