 smtp; 550 5.1.1 <ouvelis@quick.cz>: Recipient address
    rejected: undeliverable address: host 160.218.169.67[160.218.169.67] said:
    550 5.1.1 <ouvelis@quick.cz>: Recipient address rejected: User unknown in
    virtual mailbox table (in reply to RCPT TO command)
