Hello,
Is it a local account or a Microsoft account name you changed? What is the difference between a Microsoft account and a local account - Microsoft Community. What's the error message prompt?
Starting your device in Safe Mode can help troubleshoot sign-in problems.
To restart in Safe Mode:
- Restart your device by selecting Power > Restart. When you see the sign-in screen, hold the Shift key while you select Power > Restart
- After your PC restarts to the Choose an optionscreen, select Troubleshoot> Advanced options> Startup Settings> Restart
- After your PC restarts, you'll see a list of options. The preferred option is to select 5or press F5 for Safe Mode with Networking
Or sign in with a built-in admin account How to activate the built-in administrator on Windows 10 - Microsoft Community, after you signed in, review your account details in User Accounts by type netplwiz in search box .
Reference: Troubleshoot problems signing in to Windows - Microsoft Support
I hope this information helps.
Best regards,
Karlie Weng