I am working on customize third party MDM server with VPP and DEP. I checked the MDM Protocol reference and test the VPP api (VPPClientConfigSrv) with curl. Don't know why the API return:
{"errorMessage":"Invalid authentication token","errorNumber":9622,"status":-1}.
The token is generate from https://vpp.itunes.apple.com/?l=en and decode by base64 and using following command *I make sure the json file is exist and have contents:
curl -d @get_licenses.json https://vpp.itunes.apple.com/WebObjects/MZFinance.woa/wa/VPPClientConfigSrv
JSON file:
{"sToken":"Token which I decoded from vpptoken file"}