diff --git a/docker/rootfs/start.sh b/docker/rootfs/start.sh
index 94d6cfe..53dfc5c 100644
--- a/docker/rootfs/start.sh
+++ b/docker/rootfs/start.sh
@@ -57,7 +57,7 @@ _buildConfig() {
     echo "define('ENCRYPTION_KEY', '${ENCRYPTION_KEY:-}');"
     echo "define('FFMPEG_BINARY', '${FFMPEG_BINARY:-/usr/bin/ffmpeg}');"
     echo "define('ALWAYS_WEBP', ${ALWAYS_WEBP:-false});"
-    echo "define('ALLOWED_DOMAINS', ${ALLOWED_DOMAINS:-});"
+    echo "define('ALLOWED_DOMAINS', '${ALLOWED_DOMAINS:-}');"
     echo "define('SPLIT_DATA_DIR', ${SPLIT_DATA_DIR:-false});"
 }