It's been several months since I did any work in ArcGIS Online. I'm using a free subscription and have several maps and apps that I've built over the years and have never had an issue like this. Back a few months ago I took a voting precinct polygon shapefile and added some election data to the attribute table and created a web map. There was no issues with this. Today I'm trying to upload the same zipped shapefiles and I get a "This file is not supported" error message. I tried a couple different shapefiles and it seems to do it to all of them. I went in to ArcGIS Pro and did a "Repair Geometry" which did not resolve the issue and just for the heck of it I logged into my organizational ArcGIS Online account and created a webmap and tried to upload the same shapefile and it uploaded instantly. So why would the upload option be different for my organizational account vs the free account? It's just a zipped shapefile.
P.S. I've confirmed that the file size limits are not the problem, and permissions have not changed. I have noticed that when I go to upload a file into the web map it now says "Supported file types are CSV, GeoJSON, KML". I don't know if something has changed and you can no longer upload shapefiles or what?
Thanks!