I can't make and receive Whistle calls / having audio issues with Whistle
Some Internet providers, company networks and WiFi hot spots prevent VoIP (Whistle) calls over their networks. This is done as a security measure by the network administrators, but it will interfere with your Whistle call experience on that network.
If you are unable to make calls, receive calls, or hear audio on your Whistle Phone, follow this list of debugging tips :
Try Whistle on several different WiFi networks or over 3G. This will let you know if it is your network that is the problem or if your Whistle Phone is misconfigured.
Try contacting your Internet provider, company network administrator, or WiFi spot provider directly to see if they block VoIP traffic. If they do block traffic, see if they provide workarounds, such as device-specific exceptions to security policies.
Connect to the 3G connection if it is possible. The AT&T 3G network allows VoIP traffic.