 smtp; 550 5.1.1 <unimo@iol.cz>: Recipient address rejected:
    undeliverable address: host 160.218.169.65[160.218.169.65] said: 550 5.1.1
    <unimo@iol.cz>: Recipient address rejected: User unknown in virtual mailbox
    table (in reply to RCPT TO command)
