Hello, A user in my company cannot send email to some external users. I did a track on the fail messages and got the below result. I thought about to exclude the sender domains from Sender ID filtering. For instance, from the exemple1 I would run that shell command: Set-SenderIDConfig -BypassedSenderDomains user@mycompany.com But I am not sure about it. Could you please adviice and help me out with those 2 error messages?? EXEMPLE1 Timestamp : 07/12/2009 16:51:17 ClientIp : 102.XX.12.23 ClientHostname : GLXXXX91 ServerIp : 24.201.xxxx ServerHostname : mx.vixxxx SourceContext : 08CC4533587 ConnectorId : internet_outbound1 Source : SMTP EventId : FAIL InternalMessageId : 1030737 MessageId : <009701ca7755$5c962630$6f@xxxx.com> Recipients : {first.lastname@company.com} RecipientStatus : {550 5.1.1 unknown or illegal alias: first.lastname@company.com} TotalBytes : 26574 RecipientCount : 1 RelatedRecipientAddress : Reference : {<0bffb63e-357c-4a55-9188-286fd78c2>} MessageSubject : request Sender : user@mycompany.com ReturnPath : user@mycompany.com MessageInfo : EXEMPLE2 Timestamp : 07/12/2009 16:51:24 ClientIp : 102.XX.12.23 ClientHostname : GLXXXX91 ServerIp : 67.69.xxx ServerHostname : mxmxxxx SourceContext : 08CC45335870 ConnectorId : internet_outbound1 Source : SMTP EventId : FAIL InternalMessageId : 1030737 MessageId : <009701ca7755$5c962630$6f6fa8c0@consultem.com> Recipients : {savard.francis@mycompany, sulev@mycompany} RecipientStatus : {550 #5.1.0 Address rejected user32@mycompany, 550 #5.1.0 Address rejected user12@mycompany} TotalBytes : 26574 RecipientCount : 2 RelatedRecipientAddress : Reference : {<5185fd29-6506-4f80-b7fc-88f118dc6090>, <5185fd29-6506-4f80-b7fc-88f118dc6090>} MessageSubject : Demande d'expertise Sender : userrr@mycompany.com ReturnPath : userrr@mycompany.com MessageInfo :

Hi,It won't help to exclude the domains from the Sender ID filtering - You are trying to send mails to these domains right.Have you checked the the first.lastname@company.com is a valid e-mail address in the recipient mail system. Error message says it is not.Leif

You mean you can't send mail to external user, it doesn't have relationship with sender ID filtering in your side. Only this user can't send to this address or all users in your organization fail to do that? Thanks, Elvis

Thanks Leif Pedersen, you are right, it won't help to exclude the domains from the Sender ID filtering.Thanks Elvis, I did tried to send an email to that user from my personal email address and I got a NDR...In the header I could notice that: filter1173.zerospamIs that possible that the company reject us then?