I can't cook beans

Could be your water, too. Found this: http://ruhlman.com/2011/03/how-to-cook-dried-beans/

Make sure you are getting fresh beans (as opposed to some sitting on a shelf for eons--as it a common occurrence!). If they are not old they really should not need soaking, but for larger beans to be safe I soak mine overnight (or maybe just a few hours).
Bring to a boil, then simmer--that should be it! I add a bay leaf and a chunk of onion.

You might take a look at a recent article on these pages titled "Have We Been Cooking Beans All Wrong?"- it offers one method, and numerous readers in the comments talk about their own experiences.

If you're not at high elevation, try cooking them in a rice cooker. I get great results and in shorter time than stovetop.

First - are you soaking the beans overnight in salted water to re-hydrate them before you try cooking them? I know people say you can do a "quick" soak method, but honestly that doesn't work as well as I prefer. You aren't necessarily doing anything wrong, either. Timing for beans can just be tricky. You can also bake beans in a covered casserole or pot, at 325F they will take about an hour and a half. Sometimes older beans will take a bit longer, and you just check on them every 10-15 minutes until you like the texture. Your beans in the crockpot can still go into the oven, as could those from an Instant Pot, same temp- just watch the times and check every 10-15 minutes until you are happy. With an Instant Pot you can also simply reset to go for another five minutes, and do a quick release to check on them for doneness.

May I suggest a pressure cooker. i live at nearly 7000 feet in colorado and its the only way we can
get water hot enough to cook dried beans. But timing is everything. Soaking the slow method is essential for hard shell larger beans. Also not rushing the pressure cooker by allowing it to cool on it own. Pot of pinto beans made with real bacon lard while its snowing. Oh yes.