[SOLVED] AAAARGH! not receiving any mail at all

[kingxerxes]

hi there
after upgrading to the trunk last night, i am now not receiving mail at all. this is the log from an smtpdiag on my windows server. it shows the 451 error from cp

Code:

mail from: <james@xxx.co.uk>

Received:
250 2.1.0 Ok

Sent:
rcpt to: <alan@xxx.co.uk>

Received:
451 4.3.5 Server configuration problem

Error: Expected "250". Server rejected the recipient address.
Failed to submit mail to mail.xxx.co.uk.

also, server status reads:

217.10.144.235 (Port 23) TELNET DOWN

thanks for the needed help!