Candied almonds made In a crock pot didn't harden, are still gooey
I'm not an expert on candy-making, but it sounds to me as if you didn't heat the sugar sufficiently.  The temperature that the sugar reaches will affect the texture when it cools: 


https://www.exploratorium.edu/cooking/candy/sugar-stages.html


I'd attempt to heat it back up to hard-crack state (300°F), and see if I could recover it.

Being that I don't have a candy thermometer, I'd probably try something stupid, like spread it out on a sheet pan (on a silicone mat) and bake it in a 325°F oven 'til it got close, then turn the temperature down to 300°F and just let it sit for a while.

Candymaking generally requires pretty specific temperatures ... I'm not sure that I'd trust a crockpot unless it was one of those digital controlled ones with a temperature probe.  (but I suspect most of those are intended for meat, and may not be able to handle temperatures above 250°F)