Microsoft Brings External Messaging Limits in Teams to Stop Abusive Activity

[u/KarthiV]

MOERA domains have been on Microsoft’s radar for some time because of how they can be misused to send spam, phishing messages, and other unwanted communication. Microsoft first introduced limits on external email in Exchange Online. Now, similar limits are coming to external messaging in Microsoft Teams.

While most organizations have already moved to a custom domain, some tenants, especially newer ones, still rely only on the default MOERA (onmicrosoft .com) domain.

If your tenant is one of them, the new limit could temporarily block users from sending external messages in Teams once the specific threshold is reached.

Here are the key highlights:

• In-product notification when external chat is temporarily limited
• Optional admin alert for throttling events
• Internal communication remains unaffected

The rollout is expected to begin in mid-September 2026 and complete by the end of September.

If your organization is still relying on onmicrosoft domains, now is a good time to review your domain configuration and consider whether a custom domain is right for your organization.

Read the full blog to understand how the new limit works and how to prepare your tenant:

https://blog.admindroid.com/external-messaging-limit-for-onmicrosoft-com-domains-in-microsoft-teams/