Found a seed phrase on my computer, from 2015, 18 words, and a password, can not restore access, tried electrum 1.8v, not all words are in the BIP dictionary, what to do?

Is this any different from this wallet you were trying to recover a while back?
If it is, can you provide some more detailed information on what type of wallet it was, how long ago you created it and what sort of access you have to it now?