Your network can be the culprit causing the issue for the application. Sometimes, the network can be blocking the application usage for your phone. Several users solved this issue by resetting their network settings. Resetting network settings will renew all the information related to the network that you are using on your phone. You can reset the network settings by following the steps below:
Deciding what to say in a voicemail can be difficult. Poor quality and unprofessional voicemails come in a lot of shapes and sizes. Great voicemails strike the right balance of being concise, friendly and professional, which can be hard to do if you don’t leave them all the time.

Note: There is never a reason to give your sales pitch on voice mail. No one is there to say yes. Your objective is to make contact. Your objective is to provide enough information to create positive response.
Don' let background noise do the talking for you. Ambient noise on your recording could be sending the wrong message to your clients. The sound of your kids arguing in the distance could be the sign of a distracting work environment. Clinking glasses and restaurant chatter may leave the impression that you don't take your work seriously. When you record your voicemail greeting choose a quiet spot free from interruption, so your message is the only thing callers hear. It's also good to avoid large, cavernous spaces where sound verberates.