Can no longer invite users to the Tenant

Our tenant is unable to send guest invitations. All attempts return an "Insufficient Privileges" error.

Guest invitations were working correctly until approximately 15 users had been invited. The error began occurring immediately after that threshold, with no changes made to roles, policies, or admin settings in between.

The user account performing the invitations has not had any role or privilege changes. All external collaboration settings are correctly configured.

What we have verified

• Role assignments are unchanged
• External collaboration settings allow guest invitations
• Other tenants in the organization invite users without issues
• Issue is isolated to this specific tenant