diff --git a/mailu/mailu.env b/mailu/mailu.env
index 5a8d04d..032f0ce 100644
--- a/mailu/mailu.env
+++ b/mailu/mailu.env
@@ -31,5 +31,5 @@ WEBSERVICES=nginx
 # TLS
 TLS_FLAVOR=letsencrypt
 CERTS_PATH=/certs/letsencrypt
-TLS_CERT_FILENAME/certs/letsencrypt/live/mail.arti24.eu/fullchain.pem
+TLS_CERT_FILENAME=/certs/letsencrypt/live/mail.arti24.eu/fullchain.pem
 TLS_KEY_FILENAME=/certs/letsencrypt/live/mail.arti24.eu/privkey.pem