Alerts about deregistration and stopped Central Services

Hey guys,

I have a question about connecting to Sophos Central.

I have connected my XG Firewall to Sophos Central to try the Central Firewall Manager. After finishing my tests I unregistered it. But now I get a Fresh Alert every day that there is no communication with Sophos Central and also a message that several services have been stopped (I guess these are services were started before to communicate with Central). Is there a way to clear the warning message and "reset" the services?

Thank you in advance!