Detection Server did not update its heartbeat for at least 20 minutes

Hello,

Last night a have this error in all deteccion server :

Code     2302
Summary     BHHxxxxxx not responding
Detail     Detection Server BHHPASBUE942 did not update its heartbeat for at least 20 minutes. 

Check and the deteccion servers is uptime for more that 212 days , is any file log where I can have more information ?

Thanks for your help

Regars