Troubleshooting Tip: 'An error occurred when attempting to change this reference (system.zone), this reference must be handled manually.' when trying to add interface to SD-WAN zone with Integrate Interface option on GUI

[HarshChavda]

Description	This article describes how to troubleshoot the error 'An error occurred when attempting to change this reference (system.zone), this reference must be handled manually.' while trying to add an interface to the SD-WAN zone with the Integrate Interface option.
Scope	FortiGate v7.0+.
Solution	As shown in the following picture, the error occurs when attempting to move an interface to SD-WAN with the Integrate interface option: This error occurs when that interface is referenced in any zone on FortiGate: To resolve this error message, the interface should be removed from the referenced zone and then try to integrate the interface again. It will be added successfully without any error: It can also be solved by selecting 'Remove Member' for references for the System Zone option while trying to add an interface to the SD-WAN Zone with Integrate Interface option: Once the zone reference is removed using the 'Remove Member' option, it will add the interface to the SD-WAN zone as shown below: Related article: Technical Tip: How to add the interface in SD-WAN member without deleting references '