diff --git a/mail-server.nix b/mail-server.nix
index 02d1724..6a854d7 100644
--- a/mail-server.nix
+++ b/mail-server.nix
@@ -314,7 +314,7 @@ in {
               # Needs access to external network for user lookups
               "external_network"
             ];
-            env_file = hostSecrets.mailLdapProxyEnv.target-file;
+            env_file = [ hostSecrets.mailLdapProxyEnv.target-file ];
           };
           antispam = {
             service = {