Admin API-Dan Nash and HMAC

Has anyone used the code from Dan Nash’s public page for the HMAC Sha-1 password.
https://www.postman.com/dn1997/workspace/dan-nash-s-public-workspace/folder/6074515-fab97289-1544-478a-9ea0-28bffcc6571b?ctx=documentation

I got the hash, but still coming up with a 40103 error.