A third possibility (although the two already listed are the most likely): you are overloading the gfci. If you have two banks of lights and each draws 15 amps but your gfci is rated for only 20 amps the result would be a tripped gfci. Try this: plug in bank 1 and verify they all work properly. Unplug bank 1 and plug in bank 2, verify they all work properly. If both work when plugged in independently the problem is most likely an overload. It may require using two gfci outlets or removing a portion of the lights until they all operate correctly. Another option might be to use a larger breaker (if it is a 20 amp stepping up to a 30 amp might solve the problem); just don’t overload the circuit as that may cause a fire or electrocution hazard.
one of 2 things either you have a short most likely in a connection or you have a bad gfic
A third possibility (although the two already listed are the most likely): you are overloading the gfci. If you have two banks of lights and each draws 15 amps but your gfci is rated for only 20 amps the result would be a tripped gfci. Try this: plug in bank 1 and verify they all work properly. Unplug bank 1 and plug in bank 2, verify they all work properly. If both work when plugged in independently the problem is most likely an overload. It may require using two gfci outlets or removing a portion of the lights until they all operate correctly. Another option might be to use a larger breaker (if it is a 20 amp stepping up to a 30 amp might solve the problem); just don’t overload the circuit as that may cause a fire or electrocution hazard.
Good luck and enjoy!