Update 7/14/2025: Updated the FAQ.
As with all cloud services, Exchange Online imposes service limits to prevent misuse of Exchange Online resources and ensure availability for all users. For examp...
Updated Jul 14, 2025
Version 18.0
Blog Post
Arindam_Thokder
Microsoft
Microsoft1. can you elaborate "...messages sent from on-premises users to external recipients who are themselves hosted in EXO". Do you mean Other Exchange Online Tenant? Can you track these messages in your own tenant?
2. You are filtering emails based on message count, whereas we calculate this based on Recipient count.
1. Yes I can see messages sent from on-premise mailboxes to Other Exchange Online tenant Recipients (so external recipients) in my EXO Tenant Message trace , like this one this has been sent from an on-premise mailbox to an external recipent hosted on EXO as you can see I only see its landing on The receiving tenant ..
so my question is are these calculated on TERRL ?
2. Are not mail sent to multiple recipient decoupled in the message trace ? so if I send a message to 3 recipients will I not see 3 different message trace line ? if that is not the case how can I get the data needed cause The report provided in "Reports -> Mail flow -> Tenant Outbound External Recipients" does not give details ... so please provide me with a way to check this
- Arindam_Thokder
If you see messages sent from on-premises mailboxes to Other Exchange Online Tenant Recipients (so external recipients) in your EXO Tenant Message trace, there is a configuration issue at your end, and it is called wrong message attribution. And yes, these messages are counted. To fix the issue, watch this video where I explained the issue in detail - (99) Establishing Exchange Hybrid Mailflow - YouTube (watch the full video for better understanding. Your scenario starts at 16:30 min)
Thank you for the clarification, so this answer my first question, and I thank you for that, I am indeed in this predicament, what about my second question, how do I get a detail of the message\recipients included in the observed value ?
Thanks