dovecot lda bouncing postfix aliases

[Ian Evans]

Recently configured postfix to use the dovecot lda as I wanted to use
sieve. Got that working a few days ago but noticed that I wasn't getting
any emails to aliases. Checked the logs and saw messages like:

Mar  1 08:19:59 carson postfix/lmtp[16949]: 0DCD22016BE: to=<
sales at example.com>, relay=carson.example.com[private/dovecot-lmtp],
delay=0.07, delays=0.01/0.01/0/0.04, dsn=5.1.1, status=bounced (host
carson.example.com[private/dovecot-lmtp] said: 550 5.1.1 <sales at example.com>
User doesn't exist: sales at example.com (in reply to RCPT TO command))

Aliases were working previously and are in /etc/postfix/vmaps

Anything I need to check on the dovecot end of things to get dovecot to
recognize postfix aliases?

Thanks...reaching for my morning coffee. Info below:

Dovecot 2.2.9

# 2.2.9: /etc/dovecot/dovecot.conf
# OS: Linux 3.11.0-19-generic x86_64 Ubuntu 14.04.5 LTS ext4
auth_mechanisms = plain login cram-md5
mail_debug = yes
mail_location = maildir:/home/vmail/%d/%n/Maildir
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope encoded-character
vacation subaddress comparator-i;ascii-numeric relational regex imap4flags
copy include variables body enotify environment mailbox date ihave
namespace inbox {
  inbox = yes
  location =
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix =
}
passdb {
  args = username_format=%u /etc/dovecot/shadow
  driver = passwd-file
}
plugin {
  sieve = ~/.dovecot.sieve
  sieve_dir = ~/sieve
}
protocols = imap pop3 sieve lmtp
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0660
    user = postfix
  }
  unix_listener /var/spool/postfix/private/dovecot-auth {
    group = postfix
    mode = 0660
    user = postfix
  }
}
service lmtp {
  unix_listener /var/spool/postfix/private/dovecot-lmtp {
    group = postfix
    mode = 0600
    user = postfix
  }
}
ssl_cert = </etc/letsencrypt/live/example.com/fullchain.pem
ssl_cipher_list =
ALL:!LOW:!SSLv2:ALL:!aNULL:!ADH:!eNULL:!EXP:RC4+RSA:+HIGH:+MEDIUM
ssl_key = </etc/letsencrypt/live/example.com/privkey.pem
userdb {
  driver = passwd
}
userdb {
  args = username_format=%u /etc/dovecot/users
  driver = passwd-file
}
protocol lmtp {
  mail_plugins = sieve
  postmaster_address = postmaster at example.com
}
protocol lda {
  deliver_log_format = msgid=%m: %$
  mail_plugins = sieve
  postmaster_address = postmaster
  quota_full_tempfail = yes
  rejection_reason = Your message to <%t> was automatically rejected:%n%r
}
protocol imap {
  imap_client_workarounds = delay-newmail
  mail_max_userip_connections = 10
}
protocol pop3 {
  mail_max_userip_connections = 10
  pop3_client_workarounds = outlook-no-nuls oe-ns-eoh
}