Start up on a holding plate system definitely takes a bit longer than a thin rolled plate evaporation plate since you have to freeze down the Eutectic solution, but if you have given it 24hrs you should be in the normal cycling mode by that time for a classic spill over system.
We can assume that your compressor
is running because the plate is cooling
down, so as someone who builds and troubleshoots these type of systems every day, my first thought is to suspect the system is low on refrigerant.....but to help figure this out, we need more info or we would just be stabbing in the dark.
Can you give us the brand of system?
Next, does the system have a sight glass to access the state of charge?
In the event it is a Technautics CoolBlue system, here is a link to download a manual and I'm available off line to help via email