B2B guest invitations are blocked for this directory due to suspicious activity

Hello Microsoft Entra team,

B2B guest invitations appear to be blocked for our Microsoft Entra tenant.

Symptoms

• Manual guest invitation from the Azure Portal fails even when using a Global Administrator.
• The Azure Portal shows an error similar to: "Insufficient privileges to complete the operation."
• Microsoft Graph / PowerShell invitation fails with: "Invitations are blocked for this directory due to suspicious activity. Please contact Microsoft support for help."
• The issue has continued for more than 48 hours.
• We are currently unable to create a normal Azure support request for this tenant due to our available support plan.

Business purpose

This tenant is used for legitimate IT training operations.

We invite external trainees to Microsoft Teams / SharePoint sites so that they can access training materials and submit their work during training sessions.

Observed sequence

The issue occurred after the following sequence:

1. One external user was invited for license/admin setup.
2. Nine trainee users were invited successfully.
3. The next B2B guest invitation failed.
4. After that, both Azure Portal guest invitations and Graph / PowerShell invitations stopped working.

This appears to match the documented B2B invitation limit behavior for a newly created tenant. However, the tenant still appears to be blocked after more than 48 hours, so this may now be a directory-level suspicious activity block.

Request

Could Microsoft review this tenant and remove the suspicious activity block on B2B guest invitations?

I can provide the following details via private message only:

• Tenant ID
• Tenant domain
• Affected administrator UPN
• Timestamp of the failed operation
• Request ID / correlation ID
• Screenshots of the Azure Portal error
• Graph / PowerShell error output

Recurrence prevention

We will implement the following controls before resuming guest invitations:

• Daily invitation counters
• Small batch execution
• No repeated retries after invitation failure
• Immediate stop when suspicious activity or blocking errors are detected
• Reduced invitation volume for newly created tenants

Thank you for your assistance.