Drying Maroon enamel

[RiXaX]

Been a while since I've used one shot maroon on a panel, but it's been a couple days and there is still some tack. I didn't add any drier, just a tad of low temp reducer. Looks like a no sun day today, perhaps we might see some rain.

 

[Gino]

Could be several things.

Old paint
What speed reducer ?? Was that also old ??
Contaminated.
Was it sprayed or brushed on ??
If there was a thick skin, the drying agents could've been used up.