Troubleshooting Tip: Lost management access to secondary firewall (in HA) after Firmware upgrade

[AndrewX]

Description	This article describes how to make sure to access the MGMT interface to secondary firewall (HA).
Scope	FortiGate.
Solution	Background: 2 FortiGate firewalls configured in HA(A-P) and hosted in Azure running in load balancer mode. An upgrade is performed via FortiGate itself from v7.4.3 to v7.4.4, and HA is working properly. MGMT(https) access is lost on the secondary firewall, whereas SSH/Ping access is fine. Try to restart the HTTPS daemon on the secondary FortiGate firewall. Run the sniffer debug and found the package (three handshakes) working properly. Execute the http debug. However, some useful information cannot be captured. Restart the secondary FortiGate firewall. The issue will remain. Disable the https access on MGMT interface and then re-enable it again. This will fix the issues with https access to the secondary firewall.