Add native VLAN to VLAN list

[JKabaci]

I've taken over a few more duties and I am having trouble adding a native VLAN to the VLAN list. It's available on my admin switches but cannot see it on the guest switches. it's an allowed VLAN on the guest switches and when I try to add it to the native, it says it already exists. All switches are fortinet & 200E if that helps as well. 

[xshkurti]

@JKabaci 
Please check these links to add native vlan:

Administration Guide | FortiSwitch 6.4.2 | Fortinet Documentation Library

Solved: Difference between native VLAN and Untagged VLAN l... - Fortinet Community

Administration Guide | FortiSwitch 7.0.1 | Fortinet Documentation Library

[JKabaci]

Thank you and I've seen this documentation before. The problem isn't how to add the vlan to a list, it's when I try to add it, it states that it already exists but isn't populated on my native vlan list. 

[JKabaci · Accepted solution]

Solved it myself! the vlan cannot exist on both the allowed and native lists. thank you for the response and guidance with the documentation.