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:

  petriceksram na seznam.cz
    SMTP error from remote mail server after RCPT TO:<petriceksram na seznam.cz>:
    host mx2.seznam.cz [77.75.78.32]: 550 5.1.1 Sorry, no mailbox here by that name.
  z.kottnauer na seznam.cz
    SMTP error from remote mail server after RCPT TO:<z.kottnauer na seznam.cz>:
    host mx2.seznam.cz [77.75.78.32]: 550 5.1.1 Sorry, no mailbox here by that name.
  paulfranu na seznam.cz
    SMTP error from remote mail server after RCPT TO:<paulfranu na seznam.cz>:
    host mx2.seznam.cz [77.75.78.32]: 550 5.1.1 Sorry, no mailbox here by that name.
  dfsdf na email.cz
    SMTP error from remote mail server after RCPT TO:<dfsdf na email.cz>:
    host mx2.seznam.cz [77.75.78.32]: 550 5.1.1 Sorry, no mailbox here by that name.
  dawe.novotny na email.cz
    SMTP error from remote mail server after RCPT TO:<dawe.novotny na email.cz>:
    host mx2.seznam.cz [77.75.78.32]: 550 5.1.1 Sorry, no mailbox here by that name.
  drik.12 na seznam.cz
    SMTP error from remote mail server after RCPT TO:<drik.12 na seznam.cz>:
    host mx2.seznam.cz [77.75.78.32]: 550 5.1.1 Sorry, no mailbox here by that name.
  lll.lukas na seznam.cz
    SMTP error from remote mail server after RCPT TO:<lll.lukas na seznam.cz>:
    host mx2.seznam.cz [77.75.78.32]: 550 5.1.1 Sorry, no mailbox here by that name.