AV disconnections can happen for a number of reasons.  Please follow the below checks or alternatively, forward these onto your AV provider:

1. Check with your AV provider that your video EDID or setup includes an EDID emulator as well as an audio de-embedder.  These are both required for successful video playback.

2. Check your Apple adapter, if it has come loose tighten the connection and ensure strain relief is added to prevent wear-down and secure it in place.  The cables in this adapter wear down easily, so if strain relief has not been used the adapter may need replacing.

3. Check your HDMI cables, do they need replacing?

4. Check the power adapter you're using is 30W or above for Gen 3 (without the home button) iPad models.  The standard one supplied with the Gen 3 iPad is not sufficient to power video playback.

Please also refer to the below link for Virtual must have devices and equipment for successful playback: