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:

  matesprague na seznamka.cz
    SMTP error from remote mail server after RCPT TO:<matesprague na seznamka.cz>:
    host mail28.tanger.cz [212.109.183.28]: 554 5.7.1 <out10.wanadoo.es>:
    Helo command rejected: Access denied
  ruzickova.ocs na rumburk.cz
    SMTP error from remote mail server after RCPT TO:<ruzickova.ocs na rumburk.cz>:
    host rumburk-cz.mail.protection.outlook.com [104.47.17.138]:
    550 5.4.1 Recipient address rejected: Access denied. AS(201806281) [VI1EUR05FT040.eop-eur05.prod.protection.outlook.com]