How long has it been curing and how off was the mixture?

Way too little hardener = will remain tacky

Somewhat too little hardener = will cure, just more slowly

Too much hardener = will cure quickly

The specifics come down to the expoy in question and whether or not the maker pads their ratio one way or the other to make it easier to use.

If you're only somewhat off, I would give it time and you'll probably be OK. If you're way off, I would still give it time but would be less hopeful.

With polyester resin, the amount of hardener determines how fast it sets. The hardener works kind of like a catalyst bringing about a change in the resin.

With epoxy resin, you have to get the mixture right. It's two substances that react with each other and use each other up to produce a third, solid, substance. If you don't get the mixture right one of the two liquids will not be completely consumed. If it doesn't set within the pot life listed by the product, remove it, thoroughly clean the mating surfaces, and try again with the correct mixture.