Local lmtp proxy on backend server

[Marc Roos]

I receive a local mail when I do a 'mail test' on a backend svr1 with 
this[0] configuration. However when I just add only one configuration 
change 'lmtp_proxy = yes' I am getting these errors[1]. I would expect 
this email to still be delivered locally, should this be working or do I 
misunderstand the lmtp proxy functionality?


[0]
passdb {
  args =
  auth_verbose = default
  default_fields = proxy=y host=svr1
  deny = no
  driver = pam


[1]
Dec 15 23:28:48 svr1 dovecot: lmtp(9270): Debug: none: root=, index=, 
indexpvt=, control=, inbox=, alt=
Dec 15 23:28:48 svr1 dovecot: lmtp(9270): Connect from local
Dec 15 23:28:48 svr1 dovecot: auth: Debug: master in: 
PASS#0111#011test#011service=lmtp
Dec 15 23:28:48 svr1 dovecot: auth: Debug: pam(test): passdb doesn't 
support credential lookups
Dec 15 23:28:48 svr1 dovecot: auth: Debug: passdb out: 
FAIL#0111#011reason=Configured passdbs don't support credentials lookups
Dec 15 23:28:48 svr1 dovecot: lmtp(9270): Debug: user test: Auth PASS 
lookup returned temporary failure: reason=Configured passdbs don't 
support credentials lookups
Dec 15 23:28:48 svr1 dovecot: lmtp(9270): Debug: auth PASS input: 
reason=Configured passdbs don't support credentials lookups


dovecot-pigeonhole-2.2.36-3.el7_7.1.x86_64
dovecot-2.2.36-3.el7_7.1.x86_64