Hi @JH
Welcome to Microsoft Q&A! Thanks for posting the question.
As per the error message the issue is more towards your system policy that has denied the request to the SCM URL.
"Your system policy has denied access to the requested URL.
For assistance, contact your network support team."
As you are deploying using zip deployment I will suggest you to reach out to your network team and verify if *.scm.azurewebsites.net is allowed at their end.
The zip deployment will make the request to <function_app>.scm.azurewebsites.net URL.