[German]Microsoft is introducing outbound email limits for tenants to prevent misuse of Exchange Online by sending emails in bulk. This was announced by the Exchange team in February 2025. The limits were due to take effect in March 2025 and their introduction will depend on the number of licenses in the tenant. However, Microsoft has apparently postponed the introduction until April 2025.
Review of the 1st announcement
At the end of February 2025, I wrote in the German blog post Exchange Online: Tenant Outbound E-Mail-Limits ab März 2025, I had referred to Microsoft's plans to introduce a Tenant Outbound Email Limit in Exchange Online.
Microsoft calculates this Tenant External Recipient Rate Limit (TERRL) based on the number of email licenses purchased by a tenant. Microsoft's aim is to prevent the misuse of Exchange Online resources by limiting the number of outbound emails and to ensure availability for all users.
There is a special offer for customers with a high volume of emails – apart from this, Exchange Online does not support bulk emails, for example. Microsoft announced this to the tech community on February 24, 2025 in the Exchange Team Blog in the post Introducing Exchange Online Tenant Outbound Email Limits. Enforcement will be gradual and should be rolled out according to the following table.
TERRL rollout schedule
| Phase | Enable enforcement for tenant group | Rollout start date |
| 1 | Tenants with <= 25 email licenses | March 3, 2025 |
| 2 | + additional tenants with <= 200 licenses | March 10, 2025 |
| 3 | + additional tenants with <= 500 licenses | March 17, 2025 |
| 4 | + all remaining tenants | March 31, 2025 |
Based on the telemetry data, Microsoft believed that most Exchange Online customers will not be affected.
Reminder and new dates
I came across the following tweet a few hours ago, which links to the Techcommunity blog post Introducing Exchange Online Tenant Outbound Email Limits, updated by the Exchange team on March 19, 2025.
The tweet says that enforcement of the TERRL limits "will start in a week". I was surprised and looked up the dates in the Techcommunity article. They were probably postponed by Microsoft, as the following table can be found in the post.
TERRL rollout schedule
| Phase | Enable enforcement for tenant group | Rollout start date |
| 1 | Tenants with <= 25 email licenses | April 3, 2025 |
| 2 | + additional tenants with <= 200 licenses | April 10, 2025 |
| 3 | + additional tenants with <= 500 licenses | April 17, 2025 |
| 4 | + all remaining tenants | May 1, 2025 |
So everything has been postponed by exactly one month. It then goes on to say that:
- the EAC report will be enabled in the tenant on May 30, 2025
- and enforcement will be enabled on June 30, 2025
Perhaps simply take this into account.
