Extensions in a specific range can dial out but wont receive calls

Extension ranges 1 - 499 work fine when they are setup. Phone can dial out and the phone rings when they receive calls. When I set up extension 500 - 900, I can dial out but all incoming calls go straight to VM. I would like to know if there are any ranges that are reserved and if so how do I change them. Thanks in advance.

i have extensions in 5xx range and they all get calls just fine. is that range on the same inbound route ? any time conditions? CFC? that could be preventing it to get calls through ?

How do you know range is on the same inbound route? And where do I find out the CFC?

you said incoming calls. i’m assuming they’re coming from the outside. so inbound route with a DID must be specified and then it goes somewhere to IVR/Hunt Group. How does your inbound route look that handles the first range, the second or both ?