If you are trying to install ShortPoint on Office 365, and then you stuck with this step:

Installation Step 1: Upload ShortPoint to App Catalog (2 minutes)

The Issue

The issue you are facing is that you can not upload the app. It means you do not have the permission to upload apps to the app catalog site.

The Solution

You need to add the account you are logged in as an admin on the app catalog site.

Step 1: Open Site Collections Admin Center

Url will look like this: https://yourcompany-admin.sharepoint.com/_layouts/15/online/SiteCollections.aspx

Step 2: Locate the App Catalog Site Collection, then click Manage Administrators

Step 3: Add Your Account as Site Collection Administrator. Then click OK

Step 4: Wait for a couple of minutes until the loader disappears. That's it.