SIGABRT on fetching mail

Hello,

I'm usually running getmail sufficiently with dovecot for some months,
but now it seems some message is blocking my chain again, causing SIGABRT:
SimpleIMAPSSLRetriever:[email protected]@imap.gmx.net:993:
   msg 1/1 (38176 bytes) delivered, deleted
getmailrc: operation error (child pid 2995 killed by signal 6)
   2 messages (50727 bytes) retrieved, 0 skipped


Using getmail --dump, I'm getting the following output:
  retriever:  SimpleIMAPSSLRetriever(ca_certs="None", certfile="None",
getmaildir="/home/peter/.getmail/", keyfile="None",
mailboxes="('ALL',)", move_on_delete="None", password="*",
password_command="()", port="993", record_mailbox="True",
server="imap.gmx.net", ssl_cert_hostname="None", ssl_ciphers="None",
ssl_fingerprints="()", ssl_version="None", timeout="180",
use_cram_md5="False", use_kerberos="False", use_peek="True",
use_xoauth2="False", username="[email protected]")
   destination:  MDA_external(allow_root_commands="False",
arguments="('-e', '-d', '[email protected]')", command="deliver",
group="vmail", ignore_stderr="False", path="/usr/lib/dovecot/deliver",
unixfrom="False", user="vmail")
   options:
     delete : True
     delete_after : 0
     delete_bigger_than : 0
     delivered_to : False
     fingerprint : False
     logfile : logfile(filename="~/.getmail/log")
     max_bytes_per_session : 0
     max_message_size : 0
     max_messages_per_session : 0
     message_log : ~/.getmail/log
     message_log_syslog : False
     message_log_verbose : False
     read_all : True
     received : False
     verbose : 1


How can I find out, *which* message is blocking? Probably I can just
drop it, if I know ...

Kind regards,
Peter