I've just recently constructed some cut to size RGB LED strips to fit around some shelves using T & L connectors.
When I finished and connected the 12v adapter to turn them on, all the LEDs quickly flash once and then they all go out again and don't come back on. It's seems that all the strips are connected correctly so can't be a connection issue as all the light flash.
Just out of curiosity I removed that last strip that connected directly to the the power supply and turned on the power to see if that worked on it own. The same issue happened.
When I first received this 5m roll of LEDs I checked them with the power supply supplied and it all worked fine.
Any idea what might be stalling the lights staying on?