calls not bouncing to iPhone 5

[iMore Question]

Hi There,
When calls come to my work phone, it is setup to bounce to my cellphone after two rings. However lately when a call comes in it rings twice on my landline but goes straight to voicemail on my iPhone 5. My iPhone 5 just shows missed call and who called. It does not ring or vibrate.
When somebody calls my cell phone directly it goes through okay.
Could somebody help me with this?

 

[Just_Me_D]

I have no idea what could be the cause of this. The Do Not Disturb feature could be the culprit, if enabled AND if the calls that are made directly to your phone are part of your "favorites". Other than that, I have no idea. Sorry.