Black Ops Market addresses
All three open the same market. Copy one into the Tor Browser address bar.
Logging in
All three addresses at the top of this page open the same login page, because they are the same market. Use whichever one loads. What you type is identical no matter which address got you there.
Reach the login page
Any of the three addresses. Confirm the address bar before continuing, the way you already know to.
Username
The one you registered with. It is not your email address, even if you chose them to be similar.
Password
Type it yourself if you can. Password managers are fine on a machine you keep; on a borrowed machine they are a second pair of eyes.
2FA code
If 2FA is on, the code from your authenticator app. Codes roll every 30 seconds. If yours just rolled while you were typing, wait for the next one instead of entering the stale one; entering an expired code counts as a failed attempt.
When it does not take
Almost none of these are the market's fault, and the market gives you no hint about which one it is.
Keyboard layout. The market expects the characters you meant, not the ones your layout produced. If your keyboard is not US QWERTY, the classic swaps are q and g, p and semicolon, 1 and l, 6 and caret. Switch to a US layout, or type the password with the on-screen characters, one by one, looking at what appears.
The invisible extras. Caps Lock on, a trailing space from a paste, a password manager that quietly auto-filled a version of the password from before you changed it. None of these are wrong passwords. All of them report as one.
Stop hammering. Several failed attempts in a row can lock the login for a stretch of time. Take two minutes, fix the things above, try once. Patience is the cheaper error.
Forgotten things
A forgotten username and a forgotten password both go through the email the account was registered with. Check spam, wait ten minutes, check again. If that email is gone, the account is probably gone with it, which is exactly why the dedicated inbox from the start is not a formality.