This is caused by:

1. You are trying to add the tab to a personal timeline or using an app that is not published/verified

2. You are using shared SSL

The Solution

  1. Make sure you are on the latest version of Social Commerce.
    • To update, download the latest version from the website under Dashboard > My Plugins and reinstall it.
  2. Go to Social Commerce in your WordPress admin menu and ensure no SSL errors appear in Step 2 and re-add your page tab.