I have added 6 ArcGIS Online layers to an ArcMap 10.3.1 project (.mxd). When I attempt to add additional online layers: "File --> Add Data --> Add Data from ArcGIS Online" ArcMap hangs for a second, releases, and no layer is added to the Table of Contents.
I have attempted clearing the Display Cache, as well as signing out of my AGOL Account. I am using an AGOL account affiliated with a University that does not have any credit limits. I have conducted a search and not been able to find any documentation from ESRI relating to maximum number of AGOL layers in an ArcMap project.
Has anyone else encountered this behavior, or detected a maximum number of AGOL layers?