I know it's not Electrum and i know all the words are right but i think some of the words (2 or 3) are not in the right order.....
I have tried the bip39 tool on an offline pc and it says invalid mnemonic but all the words are bip39 words.
If you absolutely have no idea which words are on wrong position, even checking script can't help much because there are many possible permutation (24! / (24! - 24!) or 620448401733239439360000 possible permutation).