Reminder: Basic Authentication in Exchange Online will be switches off in 2023

Exchange Logo[German]Microsoft has reminded the days that the so-called Basic Authentication in Exchange Online will be phased out and switched off next year. Actually, this has been known for a long time and I assumed that this will already be the case from October 2022. But in January 2023, I guess it will become serious.


After all, it had already been announced in September 2021 that Basic Authentication would be disabled in Exchange Online. The cut-off date for this deactivation to begin was October 1, 2022, which Microsoft had pointed out in May 2022 (see Basic Authentication in Exchange Online will be discontinued as of October 2022). Microsoft justifies this step with the fact that Basic Auth is still one of the most frequently used methods by which Exchange Online users are compromised.

Since October 2022, tenants using Basic Auth should be randomly selected and notified with an alert. They were then to receive a 7-day warning in the Message Center (and post notices in the Service Health Dashboard) that Basic Auth in the tenant would be turned off after the deadline. Microsoft anticipated that this shutdown would be complete for all Tenants by the end of 2022.

New shutdown reminder

As of December 20, 2022, Microsoft has published the Techcommunity post Basic Authentication Deprecation in Exchange Online – Time's Up, again noting the Basic Auth shutdown. In early January 2023, Basic Authentication for multiple protocols will be permanently deprecated by Microsoft for many Exchange Online clients.

  • Beginning in early January, Microsoft will send messages to affected tenants approximately 7 days prior to the configuration change that permanently disables the use of Basic Authentication for the affected protocols (SMTP will remain untouched).
  • Shortly after the permanent disabling of basic authentication, any clients or applications that connect via basic authentication to any of the affected protocols will receive a username/password/HTTP 401 error message.

From this point on the login of clients via Basic Authentification is history. This should throw out some clients (e.g. Outlook 2007 and 2010) that do not support Modern Authentication and will then no longer work with Exchange Online. The only workaround is to upgrade the client or application, or use a different client or application that supports Modern Authentication. Microsoft has published a comprehensive support article with questions about the issue.

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