Accessing Outlook on the web for business using organizational credentials.
The OwaUserHasNoMailboxAndNoLicenseAssignedException error requires your Microsoft 365 administrator to assign an Exchange Online license to your account and verify that the mailbox is provisioned.
Assign or correct the license
An administrator with at least the License Administrator or User Administrator role should:
- Sign in to the Microsoft 365 admin center.
- Go to Users → Active users.
- Select the affected user.
- Select Licenses and apps.
- Assign a product that includes Exchange Online, and ensure the Exchange Online service within that product is enabled.
- Select Save changes. ^1^
If a license appears assigned but has an error:
- Go to Billing → Licenses and select the relevant product.
- Open Errors & Issues.
- Resolve the displayed problem, such as no available licenses, conflicting service plans, or an invalid usage location.
- Select the affected user and choose Reprocess to retry the assignment. ^1^
Allow the mailbox to provision
Mailbox creation or licensing changes normally complete in under 30 minutes but can take up to 24 hours. After assigning the license:
- Wait for provisioning to complete.
- Sign out of Outlook on the web, then sign back in.
- If access still fails, have the administrator run the mailbox-provisioning diagnostic in the Microsoft 365 admin center.
- Check Health → Service health for a relevant Exchange Online incident and resolve any user validation errors. ^2^
The diagnostic requires a Microsoft 365 administrator and is unavailable for Microsoft 365 Government, Microsoft 365 operated by 21Vianet, and Microsoft 365 Germany.
If the Exchange license was removed or expired
For a regular mailbox without a hold, removing or allowing the Exchange Online license to expire immediately disconnects the mailbox. Reassign the license within 30 days to reconnect it. After 30 days, the disconnected mailbox is permanently deleted and cannot be recovered. ^3^
Do not repeatedly remove and reassign the license as routine troubleshooting, especially if the removal date is uncertain. Assign the valid license and leave it enabled while provisioning completes.
Escalation
If the license is valid, no assignment error appears, and the mailbox remains unavailable after 24 hours, the administrator should open a Microsoft support request from the Microsoft 365 admin center. Include the UTC timestamp, request ID, session ID, and complete OwaUserHasNoMailboxAndNoLicenseAssignedException details from the error report. Microsoft’s provisioning guidance recommends escalation when the issue persists beyond 24 hours. ^2^
If you are not the Microsoft 365 administrator, send the error report and these steps to the person or provider managing your organization’s Microsoft 365 subscription.
References