If you can’t sign into your Skype account and you can’t even login after you reset the password, you can just try to update Skype.
If you haven’t updated Skype in the last 2-3 years, you might not be able to sign in, even if you enter the correct username and password.
Resetting the password will take you to some Microsoft page, you will be able to reset it but it will still not work.
Just uninstall the version that still exists on your PC and install the latest version of Skype. Then, try to login with your normal username and password.
This should fix your issue.