title: Unsupported get request error (code 100) with Facebook Graph API Ads reachestimate call
body: <p>When making requests to the reachestimate endpoint in the Facebook Ads API (v2.4), we are receiving an "Unsupported get request" error (code 100) for some users, whereas it works for the majority. Here's what I know:</p>
  
  <ul>
  <li><p>The requests are well-formed. We are providing the access token, ad account ID, currency, targeting spec, and API version. Except for ad account ID and access token, the parameters are identical between working and non-working requests.</p></li>
  <li><p>According to the access token debugger, the access tokens are valid, never expire, and contain the ads_management scope. </p></li>
  <li><p>I am able to use the same access token to successfully retrieve the Facebook page being promoted.</p></li>
  <li><p>One theory was that perhaps the users did not have permission to view the pages that were being promoted. To test this, I added an alcohol restriction to one of the pages for which the reachestimate call did work, and changed the user's age to 20. I also blocked the country in which that user was located. The reachestimate call continued to work for that user, so thus that did not reproduce the issue.</p></li>
  </ul>
  
  <p>Facebook seems to be providing a generic error that does not help determine the problem. I'm looking for any other ideas as to what it could be or how to identify it.</p>