Often this happens because you haven't defined the problem properly and accurately. Perhaps you're trying to solve a preconceived solution instead of the actual problem itself.

The problem is only what you observe, not what you imagine.

"My bloody car won't start" is a problem. "The battery is flat." is a preconceived solution to the car-starting problem. Even testing the battery doesn't prove it is the only cause of the problem. Unless you have actually recharged or replaced the battery and successfully started the car then you have no proof that the battery is the cause of the problem problem.

Simplify and keep simplifying. Break it down into small parts. If you can't solve those parts, smash them. You'll feel better. Then break it down into different small parts. Each one of those parts must be observable phenomenon.