How to set up a Cisco Paging Server?

Question

Telephony

In general, as far as I understand, this server adds the ability to implement an alert system, i.e. I pressed the button and all the phones on the speaker hear either a recording or a live broadcast.
According to the manuals, I found the following: Expand CUCM, Expand the Cisco Paging Server, and then use the Emergency Notifications Paging assistant in CUCM.
I tried to set them up, added DN 100, indicated the IP of the servers (he picked them up) and stuck the plug on the rules for determining mailing phones. Those. from which numbers it is possible - it finds the devices, and to which the message should come - it does not see a single phone through a single rule.
What could be the problem?