Why can't I authorize my Microsoft or Office 365 account?

During authenticating an Office365 account, Microsoft returns one of the following responses:

The SMTP address has no mailbox associated with it
Invalid validation response from Microsoft. Missing Email Address.
Unable to Authorize Microsoft/Office365 account 
This username may be incorrect. Make sure you
typed it correctly. Otherwise, contact your admin.
AADSTS9002313: Invalid request. Request is malformed or invalid. Trace ID: <Trace ID> Correlation ID: <Correlation ID> Timestamp: <Timestamp>, error status code: 400

Possible Causes

  • Users may be trying to connect an account without a connected mailbox. You can confirm whether they have a mailbox by checking that they have a mail address in Graph Explorer.
  • This can also occur after you complete the admin approval by inserting the mail administrator's credentials - please wait for the admin to approve.
  • The email address is an alias or unrecognised by the mail server.
  • The account is a calendar with no mailbox
  • A service account requires a mailbox.


Please pass the following instruction on to the customer / end-user trying to authenticate.

  • Visit the Graph Explorer webpage.
  • Log in with the user credentials.
  • Get the profile details by clicking on the `Get my profile`  tab.

  • Confirm a value exists for the mail field in the response.
  • Confirm that the email address is the same as they are trying to log with. If it is NOT, please reach out to the customer email administrator.

  • Confirm that the mail and userPrincipalName fields in the response are the same. When they are not the same, the aliased email address is causing the authentication process to fail. If it is NOT, please reach out to the customer email administrator to have these two fields match.



Nylas only supports accounts with a mailbox / license.


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