Deployment failed, 403 forbidden error during workflow processing

--------------------MESSAGE FROM ADMIN, DELETE BEFORE SUBMITTING----------------------

I prepared the solution in VS 2017 community edition and set the local admin, pwd, location, prefix, etc. Validation passed without any warnings or errors. Deployed the solution and it processed for about 15 minutes before failing. 3 VM's were created and are (were) running. Error details are below.

[sccm-technicalpreview](https://github.com/Azure/azure-quickstart-templates/tree/master/sccm-technicalpreview)

### Issue Details

### Repro steps (*if necessary, delete otherwise*)
1. Update/edit JSON params
2. Validate (passed)
3. Deploy
4. Fails with 403 error
[azvmtemplate-error.txt](https://github.com/Azure/azure-quickstart-templates/files/3148238/azvmtemplate-error.txt)

Start with the sccm-technicalpreview template linked in the issue and review the edited JSON parameters alongside azvmtemplate-error.txt. Reproduce the validation and deployment steps, then trace the reported 403 failure. Done means the deployment completes successfully or the template documents the required correction.

Written by the indexing model from the issue text.