Can't receive mail

[avfccolin]

I've configured my server recently and have a problem with mail, I can send mail but don't seem to be receiving any. I have configured a virtual domain also an external pop mail account . When I view the mail logs their are records of the sent mail but no records of any attempt to receive mail.
I've no idea how to trouble shoot this can anyone help please.

[avfccolin]

I've found the system logs.
this is a copy of the mail.log
ct  8 16:34:41 zentyal fetchmail[5741]: reading message xxx@popaddress.co.uk@pop.1and1.co.uk:1 of 1 (3305 octets) (log message incomplete) Oct  8 16:34:41 zentyal fetchmail[5741]: SMTP error: 451 4.6.0 Alias expansion error Oct  8 16:34:41 zentyal fetchmail[5741]:  not flushed Oct  8 16:34:41 zentyal postfix/smtpd[16756]: disconnect from localhost.localdomain[127.0.0.1] Oct  8 16:37:41 zentyal fetchmail[5741]: 1 message for xxx@popaddress.co.uk at pop.1and1.co.uk (3305 octets).
Oct  8 16:37:42 zentyal postfix/smtpd[18138]: connect from localhost.localdomain[127.0.0.1] Oct  8 16:37:42 zentyal postfix/smtpd[18138]: 38D512E01033: client=localhost.localdomain[127.0.0.1]
Oct  8 16:37:44 zentyal postfix/cleanup[18144]: warning: 38D512E01033: unreasonable virtual_alias_maps map nesting for xxx@mydomain.co.uk -- message not accepted, try again later Oct  8 16:37:44 zentyal fetchmail[5741]: reading message xxx@popaddress.co.uk@pop.1and1.co.uk:1 of 1 (3305 octets) (log message incomplete) Oct  8 16:37:44 zentyal fetchmail[5741]: SMTP error: 451 4.6.0 Alias expansion error Oct  8 16:37:44 zentyal fetchmail[5741]:  not flushed Oct  8 16:37:44 zentyal postfix/smtpd[18138]: disconnect from localhost.localdomain[127.0.0.1] Oct  8 16:38:17 zentyal dovecot: imap-login: Disconnected (auth failed, 1 attempts in 8 secs): user=<xxx@mydomain.co.uk>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured, session=<ydlwppkhjwB/AAAB> Oct  8 16:38:17 zentyal dovecot: imap-login: Disconnected (auth failed, 1 attempts in 6 secs): user=<xxx@mydomain.co.uk>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured, session=<cyiIppkhkQB/AAAB> Oct  8 16:38:29 zentyal dovecot: imap-login: Disconnected (auth failed, 1 attempts in 12 secs): user=<xxx@mydomain.co.uk>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured, session=<E1/rppkhmgB/AAAB> Oct  8 16:38:29 zentyal dovecot: imap-login: Disconnected (auth failed, 1 attempts in 6 secs): user=<xxx@mydomain.co.uk>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured, session=<Y8s/p5khmwB/AAAB> Oct  8 16:38:40 zentyal dovecot: imap-login: Disconnected (auth failed, 1 attempts in 4 secs): user=<xxx@mydomain.co.uk>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured, session=<LfoOqJkhnwB/AAAB> Oct  8 16:38:40 zentyal dovecot: imap-login: Disconnected (auth failed, 1 attempts in 2 secs): user=<xxx@mydomain.co.uk>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured, session=<YkImqJkhoAB/AAAB> Oct  8 16:38:44 zentyal dovecot: imap-login: Disconnected (auth failed, 1 attempts in 2 secs): user=<xxx@mydomain.co.uk>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured, session=</l1jqJkhowB/AAAB> Oct  8 16:38:44 zentyal dovecot: imap-login: Disconnected (auth failed, 1 attempts in 4 secs): user=<xxx@mydomain.co.uk>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured, session=<RPZEqJkhogB/AAAB> Oct  8 16:40:45 zentyal fetchmail[5741]: 1 message for xxx@popaddress.co.uk at pop.1and1.co.uk (3305 octets).
Oct  8 16:40:45 zentyal postfix/smtpd[19531]: connect from localhost.localdomain[127.0.0.1] Oct  8 16:40:45 zentyal postfix/smtpd[19531]: 764A22E01033: client=localhost.localdomain[127.0.0.1]
Oct  8 16:40:47 zentyal postfix/cleanup[19537]: warning: 764A22E01033: unreasonable virtual_alias_maps map nesting for xxx@mydomain.co.uk -- message not accepted, try again later Oct  8 16:40:47 zentyal fetchmail[5741]: reading message xxx@popaddress.co.uk@pop.1and1.co.uk:1 of 1 (3305 octets) (log message incomplete) Oct  8 16:40:47 zentyal fetchmail[5741]: SMTP error: 451 4.6.0 Alias expansion error Oct  8 16:40:47 zentyal fetchmail[5741]:  not flushed Oct  8 16:40:47 zentyal postfix/smtpd[19531]: disconnect from localhost.localdomain[127.0.0.1]







can anyone give me some advise how to fix this please