This event informs you that the time difference between your servers (SolarWinds Orion database server, NTA Flow Storage Database, and the SolarWinds NTA Service server) is above the critical threshold. The critical threshold is hard-coded to 300s.
"Time on NetFlow Receiver Service [xy] is: xxx. DB server time is xx. The difference is: 719 s. Which is above critical threshold. The data won't be correct. Synchronize the clocks and restart the service."
To resolve the issue, synchronize time settings on all servers (SolarWinds Orion database, SolarWinds NTA polling engine(s), and NTA Flow Storage Database server).