I am working on making a web app. So far I have a couple of generic layers (Counties, Municipalities etc.) and all of these are able to be queried or filtered using the widgets. I added another layer that we created with our company projects (services provided, project type, manager etc.) and this layer is not able to be selected in the Query or Filter widgets. I'm sure it's probably a simple setting that I missed but how can I get the layer to show up in these widgets?
I assuming first that it is not a secured service, so you are not dealing with proxies (which would be a different solution).
But in the Service properties for your service in ArcGIS Server, make sure the Query Capability is turned on