Invalid License Error with office 365

Daer Scott Shellhaas
Welcome, and thank you for sharing your issue in the QA forum.

Based on the information you've provided, the error InvalidLicenseException typically occurs when a user attempts to access Outlook Web App (OWA) or Exchange Online services, but the mailbox either lacks a valid license or has exceeded its assigned storage quota.

To assist you more effectively, could you kindly provide the following details:

• What type of Microsoft 365 license is currently assigned to the user? (e.g., Microsoft 365 A1, E1, E3, Exchange Online Plan 1 or Plan 2)
• Has the license been changed or reassigned recently?
• Was a large amount of data migrated that may have exceeded the mailbox quota?
• Is the error occurring in OWA, Outlook desktop, or on mobile devices?
• Has the user tried accessing the mailbox from a different browser or device?

Temporary Workaround and Technical Steps

1: Check License and Mailbox Quota

Via Microsoft 365 Admin Center:

• Go to Users > Active Users
• Select the affected user and review the Licenses and Apps section

Via Exchange Admin Center:

• Navigate to Recipients > Mailboxes
• Select the mailbox and check the Mailbox Usage section

Using PowerShell:

Connect-ExchangeOnline -UserPrincipalName ******@yourdomain.com 
Get-Mailbox -Identity ******@domain.com | FL 
Get-MailboxStatistics -Identity ******@domain.com 
Get-EXOMailboxStatistics -Identity ******@domain.com -Properties SystemMessageSize,SystemMessageSizeWarningQuota,SystemMessageCount

If the mailbox has reached its quota (e.g., 50GB for A1 licenses), consider upgrading to Exchange Online Plan 2 (100GB).

2: Reassign or Upgrade License

• Remove the current Exchange Online license
• Reassign a new license (preferably Plan 2 if additional storage is needed)
• Wait a few minutes for the system to update, then test mailbox access again

3: Check Mailbox Status

If the mailbox has been soft-deleted or marked as inactive, you may need to restore it or access it via eDiscovery tools:

• Refer to Microsoft’s guide on restoring soft-deleted mailboxes

To better understand the issue, please share a screenshot of the error message or behavior you’re encountering. This will help us provide more accurate and tailored support.

If you prefer not to share this information publicly, feel free to respond privately. I’ll follow up with a secure message to collect the necessary details.

Thank you for your cooperation. We look forward to assisting you further and resolving this matter promptly.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".   

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.