This is the most common cookie that most PHP-based websites will use. This stores the unique session ID for each visitor and enables variables to pass between page loads. The cookie only contains a reference to a session on the web server. The user’s browser won’t store any personal information. This is a session-only cookie, so it expires as soon as you close the browser.
WHMCS sets this cookie when an affiliate refers a customer to you. It stores the ID of the affiliate that made the referral so that if the customer places an order within the next 90 days following the referral, the affiliate receives credit for it. It is a persistent cookie.
WHMCS uses this cookie for the remember me functionality of the client area. The system only sets it if a client chose to have the system remember their details, ensuring that they don’t need to log in multiple times. It is persistent and lasts for 365 days, or until logout.