title: "Invalid JWT Signature." with meteor-google-oauth-jwt
body: <p>I am trying to submit a sitemap.xml programmatically, following instructions here:
  <a href="https://developers.google.com/webmaster-tools/search-console-api-original/v3/sitemaps/submit#auth" rel="nofollow noreferrer">https://developers.google.com/webmaster-tools/search-console-api-original/v3/sitemaps/submit#auth</a></p>
  
  <p>I do:</p>
  
  <pre><code>// Just call this once to set JWT
  HTTPJWT.setJWTOptions({
      email : "[ client ID up to the first dot ]@developer.gserviceaccount.com",
      key : Assets.getText("key.pem"), // Get key file from assets
      scopes : [
          "https://www.googleapis.com/auth/webmasters"
      ],
  });
  
  var submitUrl = "https://www.googleapis.com/webmasters/v3/sites/https%3A%2F%2Fwww.spoticle.com/sitemaps/https%3A%2F%2Fwww.spoticle.com%2Fsitemap.xml";
  var result = HTTPJWT.get(submitUrl);
  </code></pre>
  
  <p>... and here is the result:</p>
  
  <p>Error: failed [400] { "error" : "invalid_grant", "error_description" : "Invalid JWT Signature." }</p>
  
  <p>I can, however, generate a JWT by doing:</p>
  
  <pre><code>var jwt = GoogleOAuthJWT.encodeJWT({
      email : "[ client ID up to the first dot ]@developer.gserviceaccount.com",
      key : Assets.getText("key.pem"), // Get key file from assets
      scopes : [
          "https://www.googleapis.com/auth/webmasters"
      ]
  });
  </code></pre>
  
  <p>... but I don't know how to verify that this token is valid.</p>
  
  <p>Any help appreciated. Thanks.</p>