Troubleshooting Tip: Unable to add an interface to SD-WAN Zone as a member - Some interfaces do not show in the drop-down list

[Umer221]

Description	This article provides guidance on how to add an interface to an SD-WAN Zone as a member if it does not show in the drop-down list:
Scope	FortiOS, FortiGate, SD-WAN.
Solution	When adding a member under Network -> SD-WAN -> SD-WAN Zone -> Interface members, an interface that must be added as a member may be observed as missing: Navigate to Network -> Interfaces, and locate the interface that is missing in the SD-WAN Zone. Check for the references to that particular interface: Select the 'References' as shown in the image above. Here, LAN (internal1) has 3 references: Here, it can be seen that LAN (internal1) is in use by 3 references, which is the reason why the LAN (internal1) interface is missing from the SD-WAN Zone and cannot therefore be added as a member. To add any interface which is missing, check for the references and remove those references. Afterwards, the interface will show up in the drop-down list under the SD-WAN Zone member list. Alternately, see this article to add an interface without deleting references.