FortiAnalyzer ADOM devices show off red

I have a FortiAnalyzer 3500E v5.6.5-build1707 and have had some issues

We have configured few ADOM, but suddenly one of those ADOM start showing all registered devices in Red, like if there conectionless, but when we entered to the ADOM we can see the Devices in green and real-time log.

Any ideas why this is happen?

Regards