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:

  jirka.vlcak na email.cz
    SMTP error from remote mail server after RCPT TO:<jirka.vlcak na email.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  debilekmichal na seznam.cz
    SMTP error from remote mail server after RCPT TO:<debilekmichal na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  9gk.1edws.6la4cw5teh0.1maou8 na seznam.cz
    SMTP error from remote mail server after RCPT TO:<9gk.1edws.6la4cw5teh0.1maou8 na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  kousup112 na seznam.cz
    SMTP error from remote mail server after RCPT TO:<kousup112 na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  dreamer01 na seznam.cz
    SMTP error from remote mail server after RCPT TO:<dreamer01 na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  harpers na seznam.cz
    SMTP error from remote mail server after RCPT TO:<harpers na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  jules.r na seznam.cz
    SMTP error from remote mail server after RCPT TO:<jules.r na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  anulka.diva na centrum.cz
    SMTP error from remote mail server after RCPT TO:<anulka.diva na centrum.cz>:
    host cdx.spamfree.cz [94.242.232.66]: 554 5.7.1 <anulka.diva na centrum.cz>:
    Recipient address rejected: Access denied, user does not exist
  husky.jindra na centrum.cz
    SMTP error from remote mail server after RCPT TO:<husky.jindra na centrum.cz>:
    host cdx.spamfree.cz [94.242.232.66]: 554 5.7.1 <husky.jindra na centrum.cz>:
    Recipient address rejected: Access denied, user does not exist