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:

  porsche3 na seznam.cz
    SMTP error from remote mail server after RCPT TO:<porsche3 na seznam.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  roofie na seznam.cz
    SMTP error from remote mail server after RCPT TO:<roofie na seznam.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  syfon na email.cz
    SMTP error from remote mail server after RCPT TO:<syfon na email.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  coconut13 na seznam.cz
    SMTP error from remote mail server after RCPT TO:<coconut13 na seznam.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  toshu na seznam.cz
    SMTP error from remote mail server after RCPT TO:<toshu na seznam.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  phatetemp na frost.cz
    SMTP error from remote mail server after RCPT TO:<phatetemp na frost.cz>:
    host wes1-mx2.wedos.net [46.28.106.12]: 550 5.1.1 <phatetemp na frost.cz>:
    Recipient address rejected: User unknown in relay recipient table