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:

  jbrna na seznam.cz
    SMTP error from remote mail server after RCPT TO:<jbrna na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  dira.v.ponozce na email.cz
    SMTP error from remote mail server after RCPT TO:<dira.v.ponozce na email.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  ikanec na seznam.cz
    SMTP error from remote mail server after RCPT TO:<ikanec na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  srzantdunlope na seznam.cz
    SMTP error from remote mail server after RCPT TO:<srzantdunlope na seznam.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  tramall na email.cz
    SMTP error from remote mail server after RCPT TO:<tramall na email.cz>:
    host mx1.seznam.cz [77.75.78.42]: 550 5.1.1 Sorry, no mailbox here by that name.
  gustava na tiscali.cz
    SMTP error from remote mail server after end of data:
    host tax.virusfree.cz [31.7.241.27]: 554 message refused (#5.7.1) - for more information visit https://www.virusfree.cz/cs/help
  pockerman1 na libimseti.cz
    SMTP error from remote mail server after RCPT TO:<pockerman1 na libimseti.cz>:
    host mail.libimseti.cz [109.123.202.56]: 554 5.7.1 Service unavailable; Client host [62.36.20.208] blocked using bl.spamcop.net; Blocked - see https://www.spamcop.net/bl.shtml?62.36.20.208