3.7 web app that's been running for a few years now, just recently started having issues with the proxy.ashx. We have the latest .net proxy installed, ver 1.1.2, app/proxy both hosted on IIS 8.5. This is also the same machine running portal/server web adaptors.
When the app starts loading feature tables, the below request fails with: net::ERR_CONTENT_DECODING_FAILED 200 (OK)
https://app.ourdomain.com/proxy/proxy.ashx?https://gis.ourdomain.com/server/rest/services/Hosted/ReviewerDB2/FeatureServer/0/query?f=json&returnIdsOnly=true&token=1...
If I try the request without going through the proxy, everything works as-expected. So ArcGIS server and the hosted datastore are all operating normally. The ArcGIS server logs also display nothing.
Other requests through the proxy and have no issues, like below.
One last test was to comment out the proxy config from the JS web app
//esriConfig.defaults.io.proxyUrl = "/proxy/proxy.ashx"
//esriConfig.defaults.io.alwaysUseProxy = true;
Then "enable" CORS with JS API 3.7 via unsafe-eval.
<meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-eval' https://js.arcgis.com; object-src 'self'">
Everything then works as-expected, but our customer will never be able to visit a site with unsafe-eval in the header.
Any advice here? What is all of a sudden going on with our .ashx proxy? .net Windows updates? IIS 8 updates?