PayPal

You should click on the link of the email:

Paypal might change or add IPs for their servers when they need to handle more transactions. When your server receives a notification from another IP than the IPs of paypal listed in the paypal payment plugin options, you will receive an email automatically to your paypal address informing you of it. You can refresh this list of IPs by clicking on the link below. If paypal really added new IPs you should see them appear here. Otherwise, if you are sure that the IP from which the notification came from is a valid paypal IP you can add it to the list manually. If the notification came from someone else, it might be an attack attempt (if the payment has not been received on your paypal account for instance), in which case you can ignore it as the system blocked it. Finally, you can always disable this feature by removing all the IPs in the list and saving the paypal payment method options. You will always be able to retrieve the paypal IPs later on to reactivate the feature.