Introducing Exchange Online Tenant Outbound Email Limits

We faced thousands of blocked emails last week due to this sudden enforcement. I am having difficulty understanding how the limit is actually calculated. Internal-to-External plus External-to-External appears to be the closest approximation of the count displayed in Tenant Outbound External Recipients, but we have no way to monitor external distribution group expansions when sending emails externally.

This is particularly problematic because the formula 500 × licences^0.7 + 9,500 does not reflect the needs of an organization with high volumes of external communication. For 3,000 licences, this restricts mailboxes to approximately 50 external recipients per day. We are currently purchasing unused Exchange licences solely to raise the limit, but if the situation remains unchanged, we risk being blocked again.