If you are connecting a new Bigcommerce account to eCC Desktop, it will need to connect using the API connection.
Step 1: On the Bigcommerce Dashboard go to the Settings & Tools menu.
Step 2: Within the Settings & Tools menu, click Legacy API accounts.
Step 3: Create a Legacy API Account.
Step 4: Create a unique username in this area. Click Save in Bigcommerce before copying this information into eCC Desktop.
Note : the name "Admin" is likely being used by Bigcommerce account in a different area.
Step 5: Next to the username you created, in the actions column click edit.
Step 6: Copy the Username, API Path and API Token into the connect to your store area in eCC Desktop.
In eCC Desktop: