In general, the size limit for a single message sent from a Microsoft 365 email account is 100 MB. This size limit includes all attachments. A single message sent from Microsoft 365 can have a maximum of 500 recipients. If you're expecting an email and don't see it in your inbox: If you find legitimate email in your Junk Email folder, we recommend doing the following: Microsoft occasionally uses email to inform users about service features and license information. While it's important to exercise caution with email claiming to be from a trusted source, it's also important to empower yourself with the knowledge and common sense required to determine if a message is legitimate or illegitimate. The Microsoft 365 team strongly encourages everyone to familiarize themselves with phishing concepts and review available resources on how to protect yourself from phishing. Another great starting point is the UT Austin Information Security Office guide on how to detect a phishing email. Slow delivery of email originating from external sources is typically caused by a large demand on the Mail Filtering Service. If inbound emails are delayed, service administrators will address the issue to ensure prompt delivery of messages. Delays generally do not last longer than an hour. Mail between internal services take a separate path through the Mail Filtering Service and will be unaffected by inbound delays.Are there limits to the size or number of messages I can send?
What do I do if I'm missing an email I'm expecting?
Why am I receiving emails from @microsoft.com addresses?
Why is email delivery slow?
