Ring transformer turns on the light for a millisecond

My new ring transformer worked for about 5 min and now when I turn on the landscape light they blink on for a millisecond and then off.All functionality in the app is ok and it responsive and the same thing happens if I turn it on manually So I thought my landscape light fixture is at fault so I disconnected them and hooked up one single known good light with same result.Being a electrical engineer I just had to bring out the DVM and measure and I read anywhere from 4 to 8 volt where it should be 12vAny thoughts much appreciated .