If your PayPal subscription has been cancelled, it is likely that you have just added/changed/renewed a credit/debit card linked to your PayPal account.
To create a new PayPal subscription, login to the client area, select “Billing” and then select “My Invoices” from the drop-down menu.
Find and select an unpaid invoice in the list. From there, select “PayPal” as your payment method, and then click “Subscribe”. A cancelled subscription does not cancel any Network Dynamics services or invoices.