To add the license key, navigate to the ‘License’ section in the Salesforce Customer Portal Settings page, and enter the license key in the ‘License Key’ field.
To authenticate your Salesforce Customer Portal, fill up the authentication fields:
Consumer Key: Enter Connected App consumer’s key
Consumer Secret: Enter Connected App consumer’s secret key
Username: Enter the Username for Salesforce account
Password: Enter the Password for Salesforce account
Security Token: Enter the Security Token for Salesforce account
Operation Mode: Select the operation mode as a sandbox or live.
Note: If you already have a Security Token enter it or else reset your Security Token.
How to reset Security Token?
-> To Reset your Security Token, navigate to your personal settings, enter Reset in the Quick Find box, then select Reset My Security Token.
-> Click Reset Security Token. The new security token will be sent to the email address in your Salesforce personal settings.
-> For More Reference visit this link.