Fetchmail problems

[JulieRC]

I’ve installed fetchmail, postfix, procmail and qpopper on a Linux server and I am having trouble getting it all to work correctly.
My users can sent e-mail out and pull local mail ok but my problem arises when fetchmail polls the remote mail server. None of the mail gets delivered to the correct box and I get the following error ‘no recipient addresses matched declared local names’.

All the users are in the aliases file and I’ve updated the db by running newaliases.

~/.fetchmailrc

Set logfile /var/log/fetchmail.log
Set no bouncemail
Set postmaster root
Set daemon 3600

Poll [remote mail server] with proto POP3
user “user1” there with password “*****” is “user1” here
user “user2” there with password “*****” is “user2” here
user “user3” there with password “*****” is “user3” here

Aliases:
user1: user1, user1@mydomain.com
user2: user2, user1@mydomain.com
user3: user3, user1@mydomain.com

Any help would be good.
Thanks in advance

Julie