Hello. I have the HDMI extender, bought it last year at Best Buy. I use the transmitter/reciever in same room as TV (only one TV connected). They are bout 20 feet apart with no obstructions (open great room). Was working great but now every time I turn on TV I get message to check transmitter. I have to unplug the transmitter to get it to work. Any idea why this is happening and any possible resolution? Thanks in advance for your help.