No Incoming Number Shown-Caller ID Subcirbed!

Hi,

My Incoming Numbers not showing for incoming calls, I have setup ZAP CHANNEL DIDs Port Numbers.

When I place inbound call route to IVR, i get message “the number you are calling is not in service”, but when i add ANY DID /ANY CLID, I get the call successfully. I checked the CALLER ID and its works fine from ISP, but sometime it shows the number and sometime it doesnt show UNKOWN NUMBER.

Is there any security blocking to view incoming numbers, Because when I connect an analog phone direct to my landline, i can able to see the numbers. But when i connect the same landline to my asterisk, then i can able to see the incoming numbers sometime and sometime UNKNOWN NUMBER.

May I know how do i correctly configure the DID Numbers route to my IVR.
Is there any configuration to avoid blocking to view incoming numbers ?
Is there any extra configuration require or diagnose the problem.

Your repsonse will be highly appreciated

Thanks,
Sam.