Some hashes not unhashed?

What's up guys I was just curious I'm learning to make a combo with sqli dumper and I unhashed most of the hashes password s but how do I go about unhashing the ones that weren't fine. I used the program online reverse hash tool to unhash most of the hashes

A hash is a one way encryption so anything that is hashed in theory cannot be reversed back into the cleartext that was used to create the hash. With that being said the website you used most likely had a database of hashes and matching cleartext that was used to generate the hashes. If they are unsalted hashes or you have the salt you will need to bruteforce the hashes yourself in order to find the matching cleartext.

maybe your hashes doesn't contained in the online reverser hash.

If you're looking to crack hashes then I'd suggest a program called Hashcat GUI. Fairly easy to set up and if you have a good GPU you're able to crack hashes fairly quickly. Took less than 5 minutes to crack 35k hashes with a GTX 1070.