Hi
If run /usr/lib/sendmail -oQ/var/spool/mqueue-fix -q -v I see lot of
entries similar to following

Running /var/spool/mqueue-fix/l0GDqSi4006826 (sequence 2 of 16)
wp.pl': Name server timeout
<'some user@wp.pl'>... Transient parse error -- message queued for future
delivery
As you see address is wrong and sendmail hangs couple of minute to make host
name lookup.
The most strange thing is that it query also my domain

pdns[20218]: Received a malformed qdomain from XX.XX.XX.XX,
'wp.pl'.my-server-domain.pl': dropping

any idea how to stop this?