diff --git a/docker/server/entrypoint.sh b/docker/server/entrypoint.sh
index ea6e899..6d9dbc7 100755
--- a/docker/server/entrypoint.sh
+++ b/docker/server/entrypoint.sh
@@ -216,7 +216,8 @@ if [ ! -f "$CONFIG" ]; then
   fi
 
   if [ ! -z "$BACKENDS" ]; then
-    sed -i "s|#backends = .*|backends = $BACKENDS|" "$CONFIG"
+    BACKENDS_CONFIG=$(echo $BACKENDS | sed 's/ /,/g')
+    sed -i "s|#backends = .*|backends = $BACKENDS_CONFIG|" "$CONFIG"
 
     echo >> "$CONFIG"
     for backend in $BACKENDS; do