There is a Distribution List (DL) [Universal Scope] that has 39 members. When an external email is received by a user, their Outlook Rule forwards that email to the DL. All 39 members of the DL are internal recipients. Every time this rule fires off, the email forwards to most of the recipients, but not all. And a NDR message is generated stating that the sender does not have permission to send to the recipients. Note: We have other DLs that have more than 39 members and they can be sent to with no issues.

Check the message delivery restrictions here It's the same for pretty much 2010/2007/ and for 2003 check via ADUC on a PC/Server which has ESM installed.Sukh

Check the message delivery restrictions here It's the same for pretty much 2010/2007/ and for 2003 check via ADUC on a PC/Server which has ESM installed.Sukh

Its not due to the number of members in the DL. It appears there are restrictions applied on few recipients so that they accept emails only from specified people. As mentioned by Sukh, check the delivery restrictions for those recipients where you receive failure

Its not due to the number of members in the DL. It appears there are restrictions applied on few recipients so that they accept emails only from specified people. As mentioned by Sukh, check the delivery restrictions for those recipients where you receive failure

If this is an Exchange server 2007 or 2010, you may want to create a transport rule to forward the message from the server side instead of outlook rule. this is much cleaner & easy to manage process.

Hi, Please test if that user can forward the message to problematic recipient in the DL individually. If no, then please check the delivery restriction settings on that user. If yes, please clarify if the issue only occur to certain external sender. Please clarify if the issue only occur to meeting request or normal messaage. Xiu Zhang TechNet Community Support

Hi, Please test if that user can forward the message to problematic recipient in the DL individually. If no, then please check the delivery restriction settings on that user. If yes, please clarify if the issue only occur to certain external sender. Please clarify if the issue only occur to meeting request or normal messaage. Xiu Zhang TechNet Community Support

Hi, Please test if that user can forward the message to problematic recipient in the DL individually. If no, then please check the delivery restriction settings on that user. If yes, please clarify if the issue only occur to certain external sender. Please clarify if the issue only occur to meeting request or normal messaage. Xiu Zhang TechNet Community Support @Xiu - Not sure why you have marked your answer when you have just repeated what Rajitha and I have said? Sukh

Hi, Please test if that user can forward the message to problematic recipient in the DL individually. If no, then please check the delivery restriction settings on that user. If yes, please clarify if the issue only occur to certain external sender. Please clarify if the issue only occur to meeting request or normal messaage. Xiu Zhang TechNet Community Support @Xiu - Not sure why you have marked your answer when you have just repeated what Rajitha and I have said? Sukh Hi Sukh, Ok, since there's no response from customer for some days,so I assume that the issue has been solved. I just review the thread and then mark the possible post as answer which I have proposed before. I miss that there's another post which is also proposed as answer. So I will mark the others. Xiu Zhang TechNet Community Support