ISPconfig 3, dropmail issue

[Justin Albstmeijer]

mail is recognized as local, but gets bounced by dropmail..

any idea?

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Oct 6 00:05:16 mail01 postfix/pipe[1877]: B927E2A8059: to=<xxx@test.com>, relay=maildrop, delay=0.06, delays=0.02/0.02/0/0.02, dsn=5.1.1, status=bounced (user unknown. Command output: Invalid user specified. )

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/etc/postfix/master.cf:

maildrop unix - n n - - pipe
flags=R user=vmail argv=/usr/bin/maildrop -d ${recipient} ${extension} ${recipient} ${user} ${nexthop} ${sender}