Legend not showing for cached map service

I've pulled the following ArcGIS Server map service (cached) into Geocortex but I can't get it to show the legend https://maps.vcgi.vermont.gov/arcgis/rest/services/EGC_services/MAP_VCGI_IMPERVIOUS2016_WM_CACHE_v1/MapServer/legend

 

 

Any suggestions?

 

 

Steve