Hi, I have vanilla SBS2008 with Exchange running, using Smart Host. Can send emails out no problem, and until yesterday all users could receive email; now nobody can. I have checked the MX record, and it appears fine. I have checked the ports (telnet from inside and outside on port 25, fine too). Checked nslookup response on the server, also fine. So now I am at a loss. The domain is highergroundflooring.com. Feel free to telnet and send me a test email (richard@highergroundflooring.com). I have read multiple posts all over the net and nowhere can I find a solution, since all the above checks are ok. The only odd thing I notice is that when I telnet remote.highergroundflooring.com 25 and send HELO, I get the following response: 250 remote.highergroundflooring.com Hello [86.7.223.148] and the odd thing is that I don't recognise that IP address. The MX record IP address is different, so what's that 86.7.223.148 address being returned? Thanks, Richard

Found the problem: http://blogs.msdn.com/b/echarran/archive/2007/04/30/4-3-1-insufficient-system-resources-in-exchange-server-2007.aspx