Click "Forgot password?" above, enter your email, and follow the instructions sent to your inbox. If you don't receive an email, check spam folders and ensure your address is the one registered.
2FA adds a second verification step (like an authenticator app code or SMS) when you sign in. It's strongly recommended to enable it in your security settings.
Go to Device Management in your account settings, review active sessions, and revoke any devices you don't recognise. Then change your password and re-check 2FA settings.