First , You need to log into your PayPal Account .
Click your account name, and then select Account Settings.
Under the API Access heading, click Update.
And then , Under the Pre-built Payment Solutions heading, click Manage API permission.
Then , Click on clickbank checkbox .
On the Are you sure? screen, click Yes, revoke.
Tip: When you deselect the PayPal check box, your PayPal account is no longer connected to your ClickBank account.
NOTE: PayPal is a registered trademark of PayPal, Inc. The PayPal logo is a trademark of PayPal, Inc.