Hey, we're hoping to get this resolved asap.
I can create a map in ArcOnline and use the proper rest service URL's to add layers, and they'll work perfectly fine in the default map. However, when I go to create a new Application using the Web AppBuilder template with that same map, I will get a "The layer ______, cannot be added to the map" as well as "Basemap is not available, displaying default basemap" if we use a custom one.
Our older apps made with Web AppBuilder work as normal without issue, but I get the same errors when I try to make a new app and use maps that are already used successfully elsewhere. I'm not sure what the problem is but this started relatively recent (maybe to do with the updates?).