Web AppBuilder hangs when Creating Map Apps

Question

I have set up a Portal 10.5.1 server and federated an ArcGIS server on it. But I wants to create a map app, the browser just hangs without any response, it seems that the builder is accessing resources from fast.fonts.net. Are there any ways to fix the problem?

MatsHardy · Accepted Answer

Thanks for your reply. I have found out the root cause. I have setup rewrite rule on IIS. The rule forwards all requests containing the keyword proxy to other server, so some Portal requests are also forwarded.