Second user account usually fails to sign in after PC migration when the user profile or password sync gets corrupted during transfer. You can try these steps (simple and safe):
First, confirm the correct password by signing in here (to rule out sync issue): https://account.live.com/password/reset
Then on the PC, go to:
Settings → Accounts → Access work or school / Other users → select the second account → remove it → restart the PC → add it again.
If it still says “wrong password”, it’s often a cached credential issue. Do this:
Press Win + R → type netplwiz → check if the user is listed → remove and re-add the account.
Also run a system sync repair:
Settings → Accounts → Your info → sign out and sign back in with the main admin account.
If the account was migrated from Windows 10, sometimes the local profile is broken. In that case, create a new user :
Go to Settings > Accounts > Other accounts > Add account. In the pop-up window, click "I don't have this person's sign-in information," then click "Add a user without a Microsoft account." Enter a name and password for the new account and create it.
This usually resolves it quickly.