Mail delivery failed: returning message to sender

[Mail Delivery System]

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:

  j.stuna na ol.archives.cz
    SMTP error from remote mail server after RCPT TO:<j.stuna na ol.archives.cz>:
    host vade.zao.archives.cz [213.155.226.126]: 554 Service unavailable; Client host [out08.wanadoo.es] blocked by db.wpbl.info; Spam source - http://wpbl.info/record?ip=62.36.20.208