Start at the power pole and make sure the breaker and switch and or breakers are on and the plug is in tight. If you have a detachable power cord make sure it is properly attached to the trailer. Then go to the circuit breaker box which is a small probably plastic door that has the breakers and 12 volt fuses. All breakers ok? Also, double check that your power pole is live.
By the way, there are many models in the Jay Sport line and you didn't say which one is yours.
2017 SLX 195RB
2021 Jeep Grand Cherokee Summit L 5.7L V8
Andersen WDH hitch, Renogy 100 AH Lithium &
200 Watts solar panels from Renogy
Prev. '14 Jeep Grand Cherokee Overland, gas 3.6 V6