I found my old wallet from 2012 from blockchain.com with a file aes.json. I tried to import it on
https://login.blockchain.com/beta/legacy-pages/import-wallet.html it asks me for the password, which I have and should be correct, and after it asks me for a new password, when I put it nothing happens. What am I supposed to do? How can I use it?
It asks for a new password? Then you probably set a second password or password to authorize signing transactions from the wallet, the first one would only be used to access the wallet. Do you remember setting another password besides this one?
The way you reported, you probably set a second password, this means that if you don't remember it you can try to use bruteforce tools like btcrecover as instructed by RickDeckard.