Windows server 2012 R2 RDS event 500.19
After installing Remote Desktop Services recently for a client we found the portal wouldn't start correctly and we were presented with error 500.19. The solution was to do the following courtesy of https://forums.iis.net/t/1149768.aspx
-> Take IIS backup. -> Open IIS -> Click on server module node at the top of the left hand tree and choose "Modules". -> Right click on DynamicCompressionModule and choose "Unlock" -> Right click on StaticCompressionModule and choose "Unlock". -> Open desired websites -> Open Modules. -> Right click on DynamicCompressionModules and choose "remove". -> Right click on StaticCompressionModule and choose "Remove". -> Do IISRESET.
Once complete the RDS portal worked like a charm.