title: Postman mock service not accepting preflight request
body: <p>Using the Postman Pro API, i have created a Postman mock for my collection. </p>
  
  <p>I have created an example response for GET <code>/auth/jwt/login</code> which returns an example JWT token. </p>
  
  <p>I have used the mock successfully via postman (including the <code>x-api-key</code> header) but when i try and use this in the browser, adding the header into my request (using axios), Postman responds to the preflight OPTIONS request with
  <code>
  {"error":{"name":"invalidCredentialsError","message":"Please provide the required `x-api-key` authentication header."}}
  </code></p>
  
  <p>as expected the browser is stripping the x-api-key header (as per CORS spec) see: <a href="https://stackoverflow.com/questions/13994507/how-do-you-send-a-custom-header-in-a-cross-domain-cors-xmlhttprequest">How do you send a custom header in a cross-domain (CORS) XMLHttpRequest?</a> </p>
  
  <p>So how do i use the Postman mock servers from my application while in development?</p>