Technical Tip: Getting error notification when selecting the VPN tunnel interface in firewall policy

The error notification image below is received when selecting the VPN tunnel as an Incoming/Outgoing interface in the Firewall Policy.

The error notification will appear if the selected VPN tunnel interface is a member of a Zone. To resolve this find the Zone where the VPN tunnel is member.

In this image example below VPN tunnel interface 'S2S' was a member of a Zone 'vpn_S2S_zone'. Zone can be found on the FortiGate GUI under Network -> Interfaces -> Zone.

Once the Zone is identified, Select the identified Zone as an Incoming/Outgoing Interface on the Firewall Policy.

The error notification message will disappear as the correct Zone is applied where the VPN tunnel interface is a member.