Technical Tip: SD-WAN Performance SLA 'Default_DNS' Displays 'All Participants of Default_DNS Are Down' After Upgrading FortiGate to v7.6.1

After upgrading the FortiGate to v7.6.1, the 'Default_DNS' Performance SLA displays the message 'All Participants of Default_DNS Are Down.'

SLA details do not show any statistics.

Debugging the link monitor reveals that no probes are being sent from the FortiGate. Despite this, the associated routes remain present in the active routing table.

This issue has been resolved in FortiOS version 7.6.3.

General debug information required by FortiGate TAC for investigation:

1. Debugs:

diagnose sys sdwan health-check

diagnose sys sdwan sla-log Default_DNS 1

diagnose sys sdwan sla-log Default_DNS 2

diagnose debug application link-monitor -1

diagnose debug enable

<wait for 30 seconds>

diagnose debug disable

2. TAC Report:

execute tac report

3. Configuration file of the FortiGate.
4. Fortinet Support Tool data: Troubleshooting Tip: Collect GUI slowness and errors debugs via Fortinet Support Tool