Here it is:
   ~/src $ host [1]tfwno.gf
   [2]tfwno.gf has address 37.120.193.123
   Your mail domain is blacklisted.  The quick solution is to subscribe to
   the list.
   I wonder what the spam filter is there for.  It probably makes it
   harder for rare non-spam to reach the list.
   Why are you posting to this list?

References

   1. http://tfwno.gf/
   2. http://tfwno.gf/