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:

  martin.kyjovsky na imi.cz
    SMTP error from remote mail server after RCPT TO:<martin.kyjovsky na imi.cz>:
    host relay.zoner.com [217.198.120.23]: 554 5.7.1 Service unavailable; Client host [62.36.20.210] blocked using b.barracudacentral.org; http://www.barracudanetworks.com/reputation/?pr=1&ip=62.36.20.210
  dgguf na sdfsdf.cz
    SMTP error from remote mail server after RCPT TO:<dgguf na sdfsdf.cz>:
    host mail.sdfsdf.cz [159.69.125.20]: 550 5.1.1 <dgguf na sdfsdf.cz>:
    Recipient address rejected: User unknown in local recipient table
  dmqrcel na sejnam.cz
    Unrouteable address
  info na pneuexpres.cz
    Unrouteable address