It seems that the smtpd server used for this Phabricator instance sends invalid HELO command so I cannot receive any emails from it. This is the full log:
Oct 12 09:41:03 <hostname-hidden> postfix/smtpd[2879]: connect from deadalnix.me[198.245.51.212] Oct 12 09:41:03 <hostname-hidden> postfix/smtpd[2879]: NOQUEUE: reject: RCPT from deadalnix.me[198.245.51.212]: 450 4.7.1 <localhost.ovh.net>: Helo command rejected: Host not found; from=<phd@bitcoinabc.org> to=<email-hidden> proto=ESMTP helo=<localhost.ovh.net> Oct 12 09:41:03 <hostname-hidden> postfix/smtpd[2879]: disconnect from deadalnix.me[198.245.51.212] ehlo=1 mail=1 rcpt=0/1 data=0/1 rset=1 quit=1 commands=4/6
If the server uses Postfix, a simple fix might be to change the $myhostname config to a valid hostname.