VERIFIED SOLUTION i
Spectrum® RIA MapTiling request returns error "Description not found for map"
This suggests the path used in the request is pointing to an incorrect map path in the repository.
ResolutionUPDATED: October 19, 2017
With the RIA Proxy installed run a Map List request (http://<Proxy_Server>:<Proxy_Server_Port>/riaproxy?url=http://<Spectrum_Server>:<Spectrum_Server_port>/rest/Spatial/MapTilingService/mapList.json) on the MapTilingService to see what maps are available and use them in future requests.
Products Affected: Spectrum