Technical Tip: Unable to Authorize FortiSwitch, with the error: 'The following devices could not be authorized'

Description

This article details the reasons a FortiSwitch might not be authorized when connected to a FortiGate.

Scope

FortiOS.

Solution

An issue may occur where FortiGate is unable to authorize the FortiSwitch, as shown below.

When trying to authorize it in the CLI, the following error is seen.

MSFirewall # config switch-controller managed-switch
MSFirewall (managed-switch) # edit S148FPTFxxxxxx
MSFirewall (S148FPTFxxxxxx) # set sn "S148FPTFxxxxxx
MSFirewall (S148FPTFxxxxxx) # set fsw-wan1-admin enable
MSFirewall (S148FPTFxxxxxx) # set fsw-wan1-peer fortilink
MSFirewall (S148FPTFxxxxxx) # end
Create default vlan for vdom root failed
object set operator error, -7 discard the setting
Command fail. Return code -7

Solution:

This error occurs when an interface with VLAN ID 1 already exists under the FortiLink interface on the FortiGate. To resolve the issue, change the native VLAN ID from 1 to another VLAN ID or delete the existing VLAN ID 1 from the FortiLink, and then attempt to authorize the switch.