[Exim] Bounce messages don't pass ACLs

Hi,

I have a little problem with exim 4.12:
With the following ACL configuration exim does not accept
bounce messages.
I'm stock and don't know why and therefore I hope you can help
me out here.
Error: 550 Administrative prohibition


=============================================
begin acl

acl_check_mail:
  deny    hosts          = !+local_networks : !+relay_from_hosts
          dnslists      = relays.ordb.org : \
                      sbl.spamhaus.org : \
                      opm.blitzed.org
          message       = rejected because $sender_host_address is in a
black list at $dnslist_domain\n$dnslist_text
  accept  hosts          = *

acl_check_rcpt:
  accept  hosts          = :
  accept  hosts          = +local_networks : +relay_from_hosts
  require verify         = reverse_host_lookup
         message         = reverse host lookup failed
  require verify        = sender/callout=20s
         message         = local part of sender address or domain does not
exist
  deny    local_parts   = ^.*[@%!/|] : ^\\.
          message        = local part contains special characters. denied.
  accept  local_parts   = postmaster
          domains       = +local_domains
  deny    senders        = vit.de : nlb.de
          message        = relaying denied.
  accept  senders        = :
  deny    domains        = !+local_domains : !+relay_to_domains
          message        = relaying denied.
  require verify         = recipient/callout=15s
         message         = relaying denied.
  accept  domains        = +local_domains
  deny    message       = relaying denied.

acl_check_data:
  require verify         = header_sender
          verify         = header_syntax
         message         = sender could not be verified
  accept