Teams adds external message limits for MOERA-only tenants
Reviewed by Helen Jones
Microsoft says Teams will start applying outbound external-message limits in mid-September 2026 to organisations that use only their default onmicrosoft.com domain, also called a Microsoft Online Email Routing Address (MOERA). When a tenant reaches an applicable limit, users can be temporarily unable to send external Teams messages; internal collaboration is unaffected. The control is on by default, and Microsoft says an optional throttling alert will follow after the initial rollout.
A default-domain-only tenant can look fine until a project, supplier conversation, or support exchange suddenly needs external Teams chat. Because Microsoft has not published the applicable thresholds, an admin cannot sensibly treat this as a capacity setting to tune after disruption; it is a domain-configuration and support-readiness check. The change is also a useful line between test tenants and production collaboration. Teams admins need a clear answer on which production tenants still rely only on onmicrosoft.com, who owns any custom-domain work, and what the help desk should say when an external message is temporarily limited.
Analysis
Before mid-September, inventory Teams tenants that use only an onmicrosoft.com domain. For each production tenant, decide whether to add a verified custom domain and brief support staff on the temporary-limit notification.
Source note
Pulse published by Collab365 Spaces, reviewed by Helen Jones on . Cite as "Teams adds external message limits for MOERA-only tenants", Collab365 Spaces.