diff --git a/vpn-transit-gateway/vpn-config.tf b/vpn-transit-gateway/vpn-config.tf
index a52f3e3..ef495a5 100644
--- a/vpn-transit-gateway/vpn-config.tf
+++ b/vpn-transit-gateway/vpn-config.tf
@@ -1,6 +1,6 @@
 locals {
-  single_vpn_tunnel_loopback   = one([for k, v in local.vpn_settings : v.tunnel_loopback])
-  single_vpn_tunnel_ip_address = one([for k, v in local.vpn_settings : v.ip_address])
+  single_vpn_tunnel_loopback   = one(flatten([for k, v in local.vpn_settings : v.tunnel_loopback]))
+  single_vpn_tunnel_ip_address = one(flatten([for k, v in local.vpn_settings : v.ip_address]))
   vpn_tunnel_outputs = { for k, v in local.vpn_settings : k => {
     vpn_name          = k
     site              = v.site