VoIP bypass missing

Recently I was update Zangi latest version and my iOS 10.0.2. I cannot use Zangi. Its mean if I call zangi to zangi first 3 seconds only the voice is clear after that broken voice but if I use wifi with airplane mode I can use voice is clear no issue Im facing this issue only with mobile data.

Marrojas08 about Zangi Private Messenger, v3.6.6