Hi Pluie!
I don't want to give any hard spoilers, so I will be saying all this weirdly. . .
To get the password, ideally, you need to find pieces of the code throughout the timelines.
This being said - what you have attempted to use as a password is wrong, but not suuuuper wrong.
Once you have the password correct, it will work on every timeline - there is no requirement to clear other timelines (other than to get the clues) - which, if you look up the answer, you can bypass :)
I hope this has helped without ruining anything for you or others!
<3 MC