Forum OpenACS Q&A: mail question

When the system tries to send mail the following error occures.
Before this error I was recieving an error due to no local host
specified. So I ran the command Hostname localhost. The other error
went away but now this:

registered_proc blew up --- backtrace follows:
Expected a 250 status line; got:
554 buildaddr: no host
    while executing
"_ns_sendmail $smtp $smtpport $timeout $tolist $bcclist  $from
$subject $body $extraheaders"
    (procedure "ns_sendmail" line 58)
    invoked from within
"ns_sendmail  "$email" "[ad_parameter NewRegistrationEmailAddress]"
"Your password for [ad_system_name] has been changed" "Your password
for [ad_system..."
    (file
"/var/opt/www/ashland/www/admin/users/email-changed-password.tcl" line
19)
    invoked from within
"source $ad_conn(file)"
    (procedure "ad_handle_abstract_url" line 67)
    invoked from within
"ad_handle_abstract_url conn {}"Expected a 250 status line; got:
554 buildaddr: no host
    while executing
"_ns_sendmail $smtp $smtpport $timeout $tolist $bcclist  $from
$subject $body $extraheaders"
    (procedure "ns_sendmail" line 58)
    invoked from within
"ns_sendmail  "$email" "[ad_parameter NewRegistrationEmailAddress]"
"Your password for [ad_system_name] has been changed" "Your password
for [ad_system..."
    (file
"/var/opt/www/ashland/www/admin/users/email-changed-password.tcl" line
19)
    invoked from within
"source $ad_conn(file)"
    (procedure "ad_handle_abstract_url" line 67)
    invoked from within
"ad_handle_abstract_url conn {}"