Hey jmichael60,
We'd recommend reviewing this article for steps to connect your iPhone to a display. Connect iPhone to a display with a cable - Apple Support
"Connect iPhone to a display with a cable
With the appropriate cable or adapter, you can connect your iPhone to a secondary display, like a computer monitor, TV, or projector.
- Plug a Lightning Digital AV Adapter or Lightning to VGA Adapter into the charging port on the bottom of iPhone.
- Connect an HDMI or VGA cable to the adapter.
- Connect the other end of the HDMI or VGA cable to the monitor, TV, or projector.
- If necessary, switch to the correct video source on the monitor, TV, or projector. If you need help, use the display’s manual.
The adapters have an extra port so you can connect the charging cable and charge your iPhone while connected to a monitor, TV, or projector."
Its possible that the TV or app you are attempting to view on the display may not support video output to a second display.
Thanks!