~~I'm~~ In my country it's "you're barking up the wrong tree".

Here it's "barking up the wrong tree"

Don't look for snake tits

There's nothing similar, but "you're confused between porridge and gruel" comes closest.

Thats means that you are knowledgeable, but ignorant on the finer details that makes the case different. When you're troubleshooting something, it fits.

What is helpful is if you say what the saying means.

Your princess is in another castle

“Looking for apples in an orange tree.”

You're fighting windmills.

(A reference to Don Quichotte, of course)

In the UK we use your term also 'You've got your wires crossed'

You're crying over wrong grave.

Similar ones would be:
"You're standing on the hose" (you're very close to finding the solution but you just can't)
"You're bridling the horse from behind" (You're looking at the problem the wrong way)
"The other way around it becomes a shoe" (same as above)

The saying is hard to translate to English:
They can't see the forest behind the tree - that they were stuck on looking at.

An other one:
They can't find the udder between the horns.

These aren't the droids you're looking for.

Turkish has Yanlış kapıyı çalmak, meaning "to knock on the wrong door".

Applying to a place where your request cannot be fulfilled.

Portuguese has dar murro em ponta de fac, meaning "to punch the tip of a knife".

• insisting on something that apparently won't work
• insisting on doing something that always goes wrong
• persist without seeing results

italian has prendere un granchio, lit. meaning, "to catch a crab".

It indicates a gross mistake, the achievement of a much lower result than hoped for or, more rarely, purchasing something believing it to be of much higher value than it actually is. This expression, among the most common used in Italian to indicate a mistake, has its origins in fishing , particularly sport fishing. If you lower the line into the sea until you reach the seabed and touch the bottom with the hook and the bait, it may happen that a crab bites instead of a fish . As soon as the crustacean is hooked, it immediately begins to struggle violently to free itself from the hook, giving the fisherman the impression that it has instead hooked a large prey. Fishing for a crab with a rod is normally a source of disappointment for the fisherman, since it is a useless prey, which in some cases can even damage the line. The origin of the phrase was born from this disappointment, generated by the expectation of a large fish.