When creating a new store profile for eBay, you must first give eCC the required permissions to access your eBay account:
Once you click on button 1, eCC will open your internet browser and ask you to login to your eBay Account:
Once you are logged in, you must click on the "Agree" button to link you eBay account with eCC:
Now click on button 2 to retrieve the eBay token. eCC will now be able to successfully account to your eBay account.