Possible RobotsTxt Add-on

Hi,

Please could you help me to resolve an issue in Possible RobotsTxtHandler. 

I've installed this add-on in Episerver DXC vesion. Accessing this add-on in CMS is throwing error - 403 forbidden error. "You don't have permission to view this directory or this page" 

The add-on works fine in my local development environment but this is an issue only in app service from Azure environments. 

Any help is much appreciated. 

Thanks,

Suresh