Hello. We recently have been having problems with the monitors around the church flashing during the service. It seems as though the TVs lose connection with the computer for a moment. Sometimes it is once and sometimes it is several times in a row.

HDMI cables seem secure. 

Windows and EW are all up to date. 

For the life of me, I can't figure out what is causing this; it is only getting worse. 

Ideas? Thank you. 

The usual culprit for this is using HDMI cables that are longer than 25 ft long without using signal boosters. The signal degrades as the signal passes down the cable and usually anything over 25 to 35 feet it degrades to a point that it is unable to remain stable. Also lower priced, budget HDMI cables tend to degrade faster then higher quality cables which are constructed better. 

What you need is good quality cables combined with an extender such as the Cables2Go #60180 extender or ACTIVE HDMI cables that have signal boosters built in.