Pass phrase encryption not working

I am running LiteCoin Core, I have backed up (several times and have separate file copies named differently) and I encrypted the wallet once early on.

I have never withdrawn litecoin only added.

I tried sending them to another wallet and it keeps saying the passphrase is wrong but I know it is right, I wrote it down before I typed it and I had to verify it, so I know I have the right pass phrase.

What could I be doing wrong? and how can I correct it? I can see the coins in my wallet, just can’t do anything with them?

try loading one of the early backups, and check the passphrase