In ArcGIS server I have published a dynamic map service, but in ArcGIS portal while accessing same map service using add data option "Add layer from web" getting error "Accessing Data failed" while loading service. In service pooling I have set service timeout upto 300 seconds(5 minutes).
I am not getting any error while fetching data from attribute table of source MXD and querying from published service.
Best Answer
in the webmap, try changing your URL from http to https (or vice versa). Try accessing the service from the hosting server. Make sure that the service is started. Try accessing the service in a REST service. If you published with feature access, change "MapServer" in the URL to "FeatureServer".