I am using UTM 9.213-4 on an SG210 and have deployed the Sophos EndPoint Protection client on my devices - however, about 12 days ago, the clients stopped showing as "online" in the UTM WebAdmin control panel. If I open the live log, I can see that it appears that my UTM is failing to connect with Sophos:
I'm having the same issue on a ASG220 with UTM 9.352-6. I've tried rebooting and updating to the latest firmware. Existing devices are not online while new devices are not being listed at all. Everything worked fine up until 14 days ago. Turning the Webfilter off didn't help also.