Aug 10 2021 01:22 AM
Problem: NDR "Remote Server returned '550 5.1.90 Your message can't be sent because you've reached your daily limit for message recipients."
Question 1: the code 550 5.1.90 doesn't exist under code description - can MSFT fix it? https://docs.microsoft.com/en-us/exchange/mail-flow-best-practices/non-delivery-reports-in-exchange-...
Question 2: There are two recipient limits - Recipient rate limit & Recipient limit. Which one has been exeeded in case of 550 5.1.90?
Question 3: How to find in Exchange Online / M365 Security a report that shows all NDRs for a domain?
Apr 23 2024 04:44 AM
@Red Flag -I am also seeking answers to the same issue. Have you found any leads from any other sources?
Apr 23 2024 06:30 AM
@akpvenus It was long time ago and I can't recall the root cause / solution anymore. But in fact, I didn't struggle with this issue anymore. I have found some notes:
Recipient Limits
There are two recipient limits that count per-user to all outbound and internal messages
Clarification for Distribution Groups / Lists:
For the purposes of the recipient rate limit and the recipient limit, a distribution group that is stored in the organization's shared address book counts as one recipient.
In a personal distribution list, each recipient is counted separately.
NDR
Remote Server returned '550 5.1.90 Your message can't be sent because you've reached your daily limit for message recipients."
DOCS:
All limits: https://docs.microsoft.com/en-us/office365/servicedescriptions/exchange-online-service-description/e...
All NDR codes: https://docs.microsoft.com/en-us/exchange/mail-flow-best-practices/non-delivery-reports-in-exchange-...