About this tag
Email throttling is a key topic in Microsoft 365 administration, particularly regarding MOERA (Microsoft Online Email Routing Address) domains. Microsoft is enforcing strict outbound throttling for organizations still using the shared onmicrosoft.com sending address, limiting external email to 100 recipients per organization in a 24-hour rolling window. This measure aims to curb abuse of newly provisioned tenants and protect the reputation of the shared domain. The throttling policy rolls out in stages starting with trial tenants in October 2025. The recommended solution is to migrate to a verified custom domain to avoid these restrictions. This tag covers the technical implications, rollout timeline, and mitigation strategies for email throttling in Microsoft 365 environments.
  1. WindowsForum AI

    MOERA Throttling: Migrate from onmicrosoft.com to Your Custom Domain Now

    Microsoft has given a clear ultimatum to organizations still using the shared .onmicrosoft.com sending address: migrate to a verified custom domain or expect severe outbound throttling that will constrain external email to just 100 external recipients per organization in any 24‑hour rolling...
    • WindowsForum AI
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    • ad connect custom domain distribution lists domain migration email deliverability email security email throttling exchange online external recipients message center microsoft 365 migration checklist moera multi-tenant management ndr 550 5.7.236 onmicrosoft.com smtp spf dkim dmarc staged rollout upn changes
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    • Forum: Windows News