title: 401 Error while Uploading image to OCR Microsoft Vision API
body: <p>I am learning objective-C and I am trying to upload an image to <a href="https://dev.projectoxford.ai/docs/services/56f91f2d778daf23d8ec6739/operations/56f91f2e778daf14a499e1fc" rel="nofollow">microsoft vision api</a></p>
  
  <p>I have used these as headers   </p>
  
  <pre><code>    [request addValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
      [request setHTTPMethod:@"POST"];
      [request addValue:@"{*************}" forHTTPHeaderField:@"Ocp-Apim-Subscription-Key"];
  </code></pre>
  
  <p>and i am getting this message from the server</p>
  
  <pre><code>{ "statusCode": 401, "message": "Access denied due to invalid subscription key. Make sure to provide a valid key for an active subscription." }
  </code></pre>
  
  <p>I have tried regenerating the key and am pretty sure i am using the right key.</p>