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:

  fisa na mojemisto.cz
    SMTP error from remote mail server after RCPT TO:<fisa na mojemisto.cz>:
    host mail.cms.cz [5.102.48.114]: 550 5.1.1 <fisa na mojemisto.cz> User unknown; rejecting
  tomash.th na seznam.cz
    SMTP error from remote mail server after RCPT TO:<tomash.th na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  rigo14 na email.cz
    SMTP error from remote mail server after RCPT TO:<rigo14 na email.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  sokol369 na seznam.cz
    SMTP error from remote mail server after RCPT TO:<sokol369 na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  vilik001 na seznam.cz
    SMTP error from remote mail server after RCPT TO:<vilik001 na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  mairj na seznam.cz
    SMTP error from remote mail server after RCPT TO:<mairj na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.