Unable to load schema from 'http://json.schemastore.org/package' behind Proxy

[JoySurfer]

• VSCode Version: 1.17.1
• OS Version: Win7 x64

Steps to Reproduce:

1. package.json produces warning in every project:
   message: 'Problems loading reference 'http://json.schemastore.org/package': Unable to load schema from 'http://json.schemastore.org/package':

<title>ERROR: Cache Access Denied</title>

2. Proxy is set and used fine by other parts of VS Code. But no loading from json.schemastore.org,

[aeschli]

The JSON extension relies on the http.proxy, http.proxyStrictSSL and http.proxyAuthorization settings.
If these are all correctly set, but you still see the issue, please describe your environment in #12588.