Numerous complaints from folks about https://nps.maps.arcgis.com/home/item.html?id=c379cb0520c246f091917834ed22fd58 not loading in Pro (works in AGOL though!), turns out, a warning pops up about "Service Layer Credits Not Defined". Happening in 2.2 and 2.3 versions. This is a recent issue, works in ArcMap, we use this regularly. Suspect related to latest AGOL update?