Question about Optoma Whd200

The problem seems to me to be most likely with the WHD200. My units only get warm to the touch. Does the error also occur at the beginning, with still "cold" units or only with "damn hot" ones? The latter would point to a thermal cause. Could it be the configuration that is causing the units to get hot? Transmitter and receiver send and receive the signals to the front. You write "are next to each other"? My first WHD200 pair was also defective;-)

There are many possible reasons for a connection failure, including
Do the transmitter and receiver have line-of-sight?
Are the transmitter and receiver too far apart?
Is the source reliable or does it interrupt the picture?
Is the WHD200 defective?
etc.
Difficult to assess from a distance.