dovecot - Sep 2020 - ltmp delivery with ldap and prefetch

I am able to authorize and connect via imap. But I am not able to 
deliver a message via lmtp 

I am getting this error message.

passdb didn't return userdb entries, trying the next userdb


[1] dovecot-ldap.conf.ext
pass_attrs = 
uid=user,userPassword=password,host=host,homeDirectory=userdb_home,uidNu
mber=userdb_uid,gidNumber=userdb_gid
user_attrs = 
uid=%{ldap:uidNumber},gid=%{ldap:gidNumber},home=%{ldap:homeDirectory}

[2] pass / user db's
passdb {
  args = /etc/dovecot/dovecot-ldap.conf.ext
  auth_verbose = default
  default_fields   deny = no
  driver = ldap
  master = no
  mechanisms   name   override_fields   pass = no
  result_failure = continue
  result_internalfail = continue
  result_success = return-ok
  skip = never
  username_filter }
userdb {
  args = /etc/dovecot/special-userdb
  auth_verbose = default
  default_fields   driver = passwd-file
  name   override_fields   result_failure = continue
  result_internalfail = continue
  result_success = return-ok
  skip = never
}
userdb {
  args   auth_verbose = default
  default_fields   driver = prefetch
  name   override_fields   result_failure = continue
  result_internalfail = continue
  result_success = return-ok
  skip = never
}