When you have Virtual Office Mobile (VOM) for iOS v 7.3 installed on your iOS device, you receive calls that intermittently ring once and then go straight to voicemail. This may happen regardless of the endpoint you are using to retrieve the call (Virtual Office Desktop, Polycom desk phone, or Virtual Office Mobile for iOS).
Virtual Office Mobile for iOS v 7.3
Update to the latest version of the iOS app.
An issue with VOM for iOS v 7.3 intermittently causes the app to refuse incoming calls. When multiple endpoints (e.g., VOD, desk phone, etc.) are ringing and the VOM for iOS v 7.3 app receives the call, the app rejects the call for all endpoints.