I have a project that uses the TinyMCE editor to allow users to design a custom message.

The custom message can include merge fields, in the form of “Hello , here is your Annual Statement for “.

When the user wants to use a merge field, they click Insert>>Merge Fields, and a big list of fields appears in a palette. Each field is represented by a small image.

On one specific server, when the user brings up that palette, the images load very very slowly, and many of them fail with a little broken link image.

I repeated this process with the browser console, and the Networking tab shows 2000+ redirects to the site’s error page, resulting in a total transfer size of over 270MB in the process. So clearly the loading of these images is failing. I turned on Fiddler (with HTTPS decryption on as described here) to get further insight – but to my surprise the palette loads perfectly when Fiddler is turned on. I tried adding just that server to the “Skip decryption for the following hosts” list, and the problem immediately begins again. So now I suspect some kind of weird SSL cert issue on that server. But no other parts of the site are having any obvious problems, so it seems to be limited to some interaction between this TinyMCE component and a specific configuration on that server.

I’m at a bit of a loss to diagnose this further. Has anyone encountered this? Where should I look for further insight into this issue?