Email marked as spam

I just sent an email to pgsql-docs@lists.postgresql.org and got back
this error:

    This message was created automatically by mail delivery software.
    
    A message that you sent could not be delivered to one or more of its
    recipients. This is a permanent error. The following address(es) failed:
    
      pgsql-docs@lists.postgresql.org
        host magus.postgresql.org [87.238.57.229]
        SMTP error from remote mail server after end of data:
        550 This message was classified as SPAM

The message id was 20201125173409.GC26300@momjian.us.  Any idea on the
cause or correction?

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EnterpriseDB                             https://enterprisedb.com

  The usefulness of a cup is in its emptiness, Bruce Lee