Disable all add-ons. If an add-on is the cause, the script will start working after you disable the add-ons and restart Internet Explorer.
Note: multiple add-ons may be contributing to this issue. To help determine the conflicting add-ons, enable only one add-on and restart Internet Explorer. If the script fails after that add-on is enabled, it is one of the add-ons that disables JSON files.
Reset Internet Explorer security to the default settings. If the JSON file loads, then return each security setting to the previous level until you find the setting or settings that caused JSON to be disabled.
The browser is unable to run a JSON script or a POST.