Troubleshooting Tip: How to fix FortiADC High Availability active passive for undesired promotions and GUI got unavailable on v7.4.4

On FortiADC VM under the High Availability active passive scheme, there is an abnormal behavior causing undesired promotions and causing the GUI get lost on the 7.4.4 version.

First, run the get system ha-status command on each FortiADC cluster member.

Node 01:

(P) ADC01 # get system ha-status
Group ID: 1
Mode: active-passive
State: Primary
Config-Sync Source: Y
Config-Sync: Not Sync
Init Done: Yes
Serial-Number: FADVMSTMXXXXXX20
Node Id: 0
IP Address: 169.254.235.125
MAC Address: 00:00:5E:93:EB:7D
Last Change Time: Sun Dec 21 23:13:34 2025
Last Change Reason: Device FADVMSTMXXXXXX25 join ha group

Monitor Status
System
Harddisk: pass
Link
Up:
Down:

Sync statistics:
Sent Received
L4 session and persistence sync pkts: 0 0
L7 persistence sync pkts: 0 0

Device management errors:
Duplicate node id: 0
Image Version mismatch: 0
HA Version mismatch: 0
Group id mismatch: 0
Ha mode mismatch: 0
Ha node list mismatch: 0
Duplicate SN: 20448
Basic Errors: 0

Peer Count: 1
State: Secondary
Config-Sync Source: N
Serial-number: FADVMSTMXXXXXX25
Node-id: 0
IP Address: 169.254.199.24

Node 02:
(S) ADC02 # get system ha-status
Group ID: 1
Mode: active-passive
State: Secondary
Config-Sync Source: N
Config-Sync: Not Sync
Init Done: Yes
Serial-Number: FADVMSTMXXXXXX25
Node Id: 0
IP Address: 169.254.199.24
MAC Address: 00:00:5E:93:C7:18
Last Change Time: Sun Dec 21 23:35:27 2025
Last Change Reason: Device FADVMSTMXXXXXX20 join ha group

Monitor Status
System
Harddisk: pass
Link
Up:
Down:

Sync statistics:
Sent Received
L4 session and persistence sync pkts: 0 0
L7 persistence sync pkts: 0 0

Device management errors:
Duplicate node id: 0
Image Version mismatch: 0
HA Version mismatch: 0
Group id mismatch: 0
Ha mode mismatch: 0
Ha node list mismatch: 0
Duplicate SN: 17803
Basic Errors: 1

Peer Count: 1
State: Primary
Config-Sync Source: Y
Serial-number: FADVMSTMXXXXXX20
Node-id: 0
IP Address: 169.254.235.125

The duplicate serial number counter increases. However is highly suggested to confirm there is no other deployment with FortiADC or other Fortinet products. In order to discard duplicate serial numbers, it is suggested to change the group ID on the HA settings.

One of the main reasons for this behavior for this firmware version is that from the cmd.log.1617540 file (that is obtained from the debug file), it appears that the K8s auto-configuration commands are incomplete, so it will cause an error counter.

To get the debug file, consult the official documentation: Debug.

To fix this behavior, upgrade to v7.6.5 or v8.0.2

Related document:
Deploying an Active-Passive cluster