There could be several reasons for this.
1. If you have issues with inbound calls, it could be that you have not configured your phone properly. See our How To guides for instructions on how to configure a SIP Device.
2. If you are diverting your number to another number, it could be that you haven't included the country code or you do not have sufficient credit to support the divert.
3. If your subscription is for a geographic number, it could be possible that your subscription has been cancelled.
4. If you have routed the number to an external destination like your PBX or another provider, please check your details and ensure that your SIP provider is not blocking traffic.
5. Loss of Internet connectivity, check with your ISP.
If you have checked all of the above and the issue persists, contact our support team.