Cannot receive calls
This is related to the IP Handset (IP Centrex), or the Gateway Device (IBL, PRI) ability to register to VoiceMailTel network. There are a few possible causes:
1. Power Outages
2. Loss of Internet Connectivity
3. Router / Firewall security settings blocking VOIP traffic.
Note: Calls should still route to Auto Attendent and/or VM. Customers can also choose emergency routing options, i.e. route to cell phones or landlines.