diff --git a/Dockerfile b/Dockerfile
index ea1f6447..8d7ba56c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -91,6 +91,7 @@ ENV VPN_SERVICE_PROVIDER=pia \
     OPENVPN_CIPHERS= \
     OPENVPN_AUTH= \
     OPENVPN_PROCESS_USER=root \
+    OPENVPN_MSSFIX= \
     OPENVPN_CUSTOM_CONFIG= \
     # Wireguard
     WIREGUARD_ENDPOINT_IP= \