I'm using a Small Business Server 2003 with Exchange 2003.
Two problems occur regularly:
1. When I send internet mails to some mail domains I receive a NDR with the code 4.4.7. This started about 3 month ago. With most of the mail domains I still have no problems sending mails to them. Just some mail domains don't work (but always the same). I already checked the blacklist for open relay server but my domain is not listed. Also the relay setting in the SMTP Virtual Server is not open (standard setting). Since I have not made any changes I don't understand why I could send mails to any domain before and now some make problems.
2. When I replay on a mail which I received thru a distribution list sometimes I receive a NDR with the code 5.7.1 (You do not have permission to send to this recipient). When I try to resend the same mail a few minutes later it goes thru without any problems. Why and what can I do to fix it?
Could anyone give me some help on these two problems?