gitlab fatal: Authentication failed for code example
Example 1: remote: HTTP Basic: Access denied fatal: Authentication failed for
git config --system --unset credential.helper
Example 2: git https basic access denied
Go to Windows Credential Manager. This is done in a EN-US Windows by pressing the Windows Key and typing 'credential'. In other localized Windows variants you need to use the localized term (See comments for some examples).
alternatively you can use the shortcut control /name Microsoft.CredentialManager in the run dialog (WIN+R)
Edit the git entry under Windows Credentials, replacing old password with the new one.