Hello Update16,
Thank you for reaching out to Apple Support Communities.
We were able to find this:
"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."
More details can be found here: Connect iPhone to a display with a cable
If the issue persists, can you provide a few more details? Have you tested with another HDMI cable, Adapter, or display? Also, what is your exact iOS version?
Cheers!