It did work from Postman without issues but recently it just stopped - I can get metadata for any other app using contentMetadataLookupUrl service, but the moment I use appId for the B2B app it returns no metadata.
Here's an example from Postman:
GET /WebObjects/MZStorePlatform.woa/wa/lookup
cache-control: no-cache
Postman-Token: fbc220f0-26ad-42d8-b5da-12fe1cd85036
User-Agent: PostmanRuntime/7.6.0
Accept: */*
Host: uclient-api.itunes.apple.com
cookie: itvt=[...]
accept-encoding: gzip, deflate
HTTP/1.1 200
status: 200
x-apple-jingle-correlation-key: 3JSTXMC3YD6SKNTOM7CWRM4UIE
x-apple-application-site: NWK
access-control-allow-origin: *
apple-originating-system: MZStorePlatform
content-encoding: gzip
strict-transport-security: max-age=31536000
apple-tk: false
apple-seq: 0
date: Fri, 08 Feb 2019 03:46:37 GMT
apple-timing-app: 20 ms
cache-control: max-age=900, no-transform
content-type: application/json; charset=utf-8
x-apple-application-instance: 1010002
x-webobjects-loadaverage: 0
x-apple-request-uuid: da653bb0-5bc0-fd25-366e-67c568b39441
content-length: 122
Connection: keep-alive
{"results":{},"version":1,"isAuthenticated":false,"meta":{"storefront":{"id":"143455","cc":"CA"},"language":{"tag":"en-ca"}}}
