Microsoft is introducing new limits for onmicrosoft.com domains. Organizations can now send a maximum of 100 external emails per day via these standard domains to prevent spam. The new measure limits messages from onmicrosoft.com domains to 100 external recipients within 24 hours. Previously, there were no limits for Microsoft Online Email Routing Address (MOERA) domains. Microsoft is responding to an ongoing issue within Microsoft 365. Spammers are abusing new tenants to send large amounts of unwanted emails before Microsoft can intervene.