diff --git a/tools/create-vpn-keys.sh b/tools/create-vpn-keys.sh
index 1ea1bf7de4a2a5d9951391eeff0b3ba940dd46c3..f07fbebe042bb94a47f62f872a25ec4b5ea8295d 100755
--- a/tools/create-vpn-keys.sh
+++ b/tools/create-vpn-keys.sh
@@ -21,7 +21,7 @@ fi
 SRC=$(dirname $0)
 VPN_SECRETS=$(dirname $1)/secrets/monitoringvpn
 
-CONFIG=$(nix eval --json -f "${SRC}"/get-vpn-config.nix --arg pathToGrid "${1}" vpn)
+CONFIG=$(nix-instantiate --strict --json --eval "${SRC}"/get-vpn-config.nix --arg pathToGrid "${1}")
 
 MONITORING_IPS=$(echo $CONFIG | jp --unquoted "join(' ', clientIPs)")
 VPNSERVER_IP=$(echo $CONFIG | jp --unquoted "serverIP")