Miscellaneous topics that do not fit into specific categories.
If the domain was newly added in Microsoft 365, mail can fail temporarily for two common reasons:
- The domain is still replicating across Exchange Online servers. This can take up to 1 hour.
- The MX record is missing or still replicating across DNS servers. This can take up to 72 hours.
If the domain itself is expired or on hold, users on that domain no longer receive email until the domain is active again. In Exchange Online, alerts can appear when a domain is expiring within 90, 60, or 30 days.
If the issue started after adding or changing the domain, check Microsoft 365 admin center > Setup > Domains and review the Status column. If there is an issue, select the three dots and choose Check health to see what DNS or domain problem needs to be fixed.
If the domain was purchased as an Azure App Service domain, it is valid for 1 year from purchase. It can be renewed manually up to 90 days before expiration, or set to renew automatically.