Accessing Outlook on the web for business using organizational credentials.
Your organization’s Microsoft 365 administrator must assign your account a license that includes Exchange Online and confirm that the mailbox finishes provisioning.
The exception OwaUserHasNoMailboxAndNoLicenseAssignedException specifically indicates that Outlook on the web cannot find an Exchange mailbox or applicable license for the account.^1^ Being able to use other Microsoft 365 services does not mean that Exchange Online is enabled.
What to send your IT administrator
Send this message to your IT/help desk:
My account can sign in to other Microsoft 365 services, but Outlook on the web returns
OwaUserHasNoMailboxAndNoLicenseAssignedException. Please verify that my account has an active license containing Exchange Online, that the Exchange Online service is enabled, and that my mailbox has provisioned successfully.
Do not include the client ID, session ID, request ID, or other diagnostic identifiers in a public post.
Administrator steps
An administrator should:
- Open Microsoft 365 admin center → Users → Active users.
- Select your user account.
- Select Licenses and apps.
- Assign an available Microsoft 365 or Office 365 product license that includes Exchange Online.
- Expand Apps and ensure the relevant Exchange Online service is selected.
- Select Save changes.^2^
If the correct license is already assigned, the administrator should check for license-assignment or user-validation errors and run the mailbox-provisioning diagnostic from the Microsoft 365 admin center. Microsoft states that provisioning normally takes less than 30 minutes but can take up to 24 hours.^3^
After the change, sign out of Microsoft 365 and retry Outlook on the web once provisioning has completed. Browser-cache clearing or reinstalling Outlook will not create a missing Exchange mailbox.
If it still fails after 24 hours
The administrator should:
- Check Microsoft 365 admin center → Health → Service health for a relevant Exchange Online incident.
- Confirm that the account has no unresolved validation or license-assignment errors.
- Open Help & support in the Microsoft 365 admin center and submit a support request if the mailbox remains unprovisioned after 24 hours.^3^
References