MacBook Air keeps rejecting my correct Mac login password for password-protected features

I recently bought a brand-new 13-inch MacBook Air and transferred all my files and data from my Windows PC. I am running macOS 27.2.

Setting up the Mac went smoothly until I was prompted to enter my Mac login password to enable Touch ID, open the Passwords app, and access other password-protected features.

The problem is that my Mac keeps rejecting my password whenever I try to authorise these actions.

To clarify, I am specifically prompted to enter my Mac login password, not my Apple Account/iCloud password. I am entering the correct password for the account on my Mac, and I know it is correct because I can successfully log in to my MacBook using that exact same password. I have even double-checked it character by character, but it is still rejected when I try to authorise these actions.

So far, I have tried some basic troubleshooting, including changing my Mac login password and restarting the computer. I also tried to access Keychain to check whether there might be a mismatch between my current login password and the password stored in Keychain. However, I cannot access it because my Mac rejects my password there as well.

Since this is a brand new MacBook, I am confused as to why this is happening. I can log in to the computer without any problems, but I cannot use the same password to authorise actions that specifically ask for my Mac password.

I am getting increasingly frustrated because I cannot figure out what is going wrong. I am starting to doubt myself and my limited tech skills, so I would really appreciate any advice or suggestions on how to resolve this issue.

Any help would be greatly appreciated!