Geocortex Reporting and Printing JWT validation errors occur when using the toolset externally through Azure App Proxy

I have an instance of ArcGIS Enterprise 10.7.1 installed on-premise with Geocortex Reporting version 5.5.0 and Printing version 5.2.0 installed. The Geocortex Reporting application works ok when working with the tool from within our internal network. However, there appears to be a JWT validation error that occurs when working with the tool from outside our network. I currently have external access to ArcGIS Portal configured through Azure App Proxy. The error occurs when generating and downloading the PDF reports through the Reporting and Printing widget.

Error: An error occurred while validating the JWT: Newtonsoft.Json.JsonReaderException: Invalid property identifier character: (. Path '', line 1, position 1.\"

\"id\": \"GR001.400\",\r\n   \"message\": \"GR001.400: Bad Request\",\r\n   \"status\": 400\r\n },\r\n \"final\": true,\r\n \"log\": {\r\n   \"start\": \"2019-12-20T16:27:09.9412988Z\",\r\n   \"end\": \"2019-12-20T16:27:09.9603012Z\",\r\n   \"errors\": 1,\r\n   \"artifacts\": [\r\n     {\r\n       \"$type\": \"JobTokenError\",\r\n

Is there anyone else out there that has a similar configuration accessing the toolset externally via Microsoft Azure App Proxy and experiencing a similar error? Any ideas what I need to do to correct this issue and get the Geocortex applications working properly through Azure App Proxy?