Iframe doesn't render a local page when src is local and redirected to remote then back to local
Hi and sorry for the vague subject line.
Here is the situation. On one page of the site an iframe is rendered. The src element of the iframe is a local url. The src url will render an html page which is simply an html form that posts to a remote url. The remote site will do some internal posts and then finally sends a get request back to my app. The final step is to render a local page from my app. All that should happen within the iframe.
With Firefox the final page is not rendered. I can debug the site and I see the final get request is processed on the server but Firefox doesn't display the page. I've tried returning a redirect to the final page instead of returning the html and then I can see in the dev tools a get request to that (local) url however I just get a blank page in the iframe.
All this is using https urls. Any suggestions are appreciated.