Error with the mail messages
 

Hello,

i have a problem with a mail message. Sometimes i receive deamon from
Blackberry network, for example

The mail system

<anyhost2_at_email.cz>: host 77777.seznam.cz[xxx.xxx.xx7.47] said: 550 5.7.1
Sender Policy Framework of `srs.bis7.eu.blackberry.com' domain denied your
IP address. (in reply to MAIL FROM command)

This mail receive anyone inside the network. What i can do to prevent it ?