Please follow the steps below and It?l help you to connect the phone to TV.
Connect The HDMI cable with TV first and then with the adapter.
Connect the Power/Charging cable with the adapter and wait for few seconds.
Connect the mobile with the adapter and again wait for few seconds until you get the mobile display on TV.
Notes : (please pay attention to use)
Select "Trust" if prompted.
Use certificated for lightning cables, HDMI cables and AC power chargers.
iOS version 10.1 or later.
It might take up to 30 seconds to reflect on the TV screen.
Connect the HDMI cable and charging cable first, and then connect to the iPhone.