Cannot record Phone Conversation via headphone Jack


I opened a project ( c8.5), and made two audio tracks with inputs from U-Phoria Behringer Audio interface… One for myself with input from my microphone and another mono track with input from my iPhone using 1/8" stereo cable.

When I payback music from my iPhone, I can record it into cubase. However, when I talk on the phone with the person, the person’s voice seems is not recording. It seems the gain is very low which I can increase the signal volume using Normalize process.

Is this because I am not using the right cable ( say a digital) or what?

Any help would be greatly appreciated.