Why am I only get audio calls on iPhone?

After we added the two-way video for a call generated by pressing the doorbell button to the WUUK iOS app, there are two different scenarios for a user to receive the call:

• When your iPhone screen is locked
• When your iPhone is NOT locked

For an unlocked iPhone screen, you will receive a call like this:

Once you slide to answer, it is automatically a two-way video call.

If your iPhone is under a locked screen situation, the incoming call from WUUK Doorbell looks like this:

You need to first pick up the call from WUUK Audio, and then press the WUUK logo icon to enter into the two-way video call.