When attempting to add an app to the Intune portal using the Intune Software Publisher as described here you get the following error message:
Reviewing the WindowsIntuneSoftwarePublisher.log in C:\Users\username\AppData\Local\Temp\SoftwarePublishing
Shows the following error “The remote server returned an error: (401) Unauthorized”
In my case, while the user account used to add the app to Intune was a global admin, it did not have an EM+S license assigned.
The solution was to assign an EM+S license to the account
After that, the app data uploaded successfully to Intune