When I publish a form based on your Excel file, I can see the same error; in fact, the error also occurs when trying to add a point via the ArcGIS Online Map Viewer, which indicates a problem with the service. One aspect I noticed is the long name of your Excel sheet (77 characters), which creates an equally long table name when published. I was able to publish with a shorter name and add data successfully.
Thank you so much.
Retrieving data ...