First time in ArcGIS Pro. I added a map service - tried both from AGOL and connecting straight to my ArcGIS Server (10.2.1). The top level of the map service shows a lighter gray checkmark next to it and none of the layers are visible at the scales I've got them set to draw in the map service.
When I open up the layer properties, the visibility range has In beyond and Out beyond both set to 1:4,622,324 (which I definitely don't have set in my map service - I can see it in the regular arcgis.com viewer, and in arcgis desktop just fine).
The one thing that may be odd about this map service is that all the layers are defaulted to unchecked to start because it shows all our facility and the user in other apps has to pick which group they want to view rather than have them all draw from the start.
I tried another map service that seems to display just fine from the same server.