I'm having a persistent problem with a real troubling inconsistency in importing existing layers hosted online. I've got data that served my maps perfectly well in ArcMap 2.1, but it's completely unreliable in Pro.
I import my map files into a blank Pro project. Sometimes, everything imports fine. Sometimes, data-set references are broken (little red exclamation point in the layer panel). So I try to manually help Pro re-discover the referent. Whether by clicking the red exclamation point, navigating through the portal, or adding data, I cannot get ArcGIS Pro to respond the way advertised. Sometimes, the lost data-set imports without incident. Sometimes, it doesn't matter what method I use to import, nothing happens after the loading animation finishes. No layers are added, no links refreshed, the red exclamation point remains, and my data do not appear on the map.
Can someone help me?