When some users get this error "There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. <myservername.mydomain.local #5.5.0 smtp;554 From Domain must match authentication Domain [R0107004]>" Let you know about my setup. I am running SBS 2003 sp2 with Exchange sp2 and just installed sbs sp1 this was for the Best practices analyzer in order to migrate to sbs 2011. My users use various ver of Outlook 2000 to 2007 they are also setup as dual exchange services and internet mail services. I have Exchange routing through virtual SMTP to my connector and the connector is setup to forward all mail through this connector to the following smart host aka ISP SMTP I checked the virtual SMTP and I have ID filtering off this is only happening on the users that have a different user login on isp internet mail then local domain login, the users have both exchange and internet services Could you tell me what I am missing thanks.

That is an error being generated by your ISP. It isn't an Exchange error. You will need to contact them to establish whether they can support additional domains through their smart host. Many can, but you have to tell them. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

well it all started after I put sbs sp1 on and <myservername.mydomain.local #5.5.0 smtp;554 From Domain must match authentication Domain [R0107004]>" says my server and my local domain wihch is different from my email domain.

Doesn't really matter when it started, it isn't an Exchange error. You need to speak to your ISP to ask about what they need to do to allow you to use their smart host. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Hi Maybe this KB is useful to you. http://support.microsoft.com/kb/300171Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.