On the project I’m working at the time of this post, I was using an IIS project as a proxy using rewrite rules. One day a random config changed and I got blank page whilst using the proxy. Fixing this required lots of diging around but the solution was to use IIS Manager to unlock the allowedServerVariables config section from the application host.

Follow the screenshots below if you are having a similar issue.

redirect1 redirect2 redirect3 redirect4 redirect5 redirect6