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:

  poi.lkj.mnb na seznam.cz
    SMTP error from remote mail server after RCPT TO:<poi.lkj.mnb na seznam.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  tomash.th na seznam.cz
    SMTP error from remote mail server after RCPT TO:<tomash.th na seznam.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  mcgrotiel na seznam.cz
    SMTP error from remote mail server after RCPT TO:<mcgrotiel na seznam.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  freshcock na email.cz
    SMTP error from remote mail server after RCPT TO:<freshcock na email.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  david19 na seznam.cz
    SMTP error from remote mail server after RCPT TO:<david19 na seznam.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  blebes na seznam.cz
    SMTP error from remote mail server after RCPT TO:<blebes na seznam.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  fugyv na seznam.cz
    SMTP error from remote mail server after RCPT TO:<fugyv na seznam.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  jakubzburnik na seznam.cz
    SMTP error from remote mail server after RCPT TO:<jakubzburnik na seznam.cz>:
    host mx1.seznam.cz [77.75.76.42]: 550 5.1.1 Sorry, no mailbox here by that name.