I'm trying to add a field to an AGOL hosted feature service and am getting the above error. I can't find any setting that changes anything and it's quite problematic. I'm in the item details page, under the "data" tab.
I'm the data owner, and editing is currently set to disabled. There are two views configured from the original Feature Service, with editing disabled on both. I've tried with it enabled without any luck as well. I've also tried adding a field by opening the FeatureService in ArcGIS Pro without any luck.
Anyone have a similar issue? Any help much appreciated.