Hi, I have the same issue. I am not receiving any server to server notifications anymore in the sandbox environment. Last notification I received was yesterday evening November 3th ( UTC + 1 ).

Hi, I am also experiencing issues in the sandbox environment today. I do not receive any server to server notifications anymore. I am also getting "Your payment method was declined" in the Sandbox environment for no obvious reason from time to time. Also sometimes when I try to renew a subscription, it just shows a spinning wheel for some time and then it just stops. Kurt