diff --git a/birdnet-pi/rootfs/custom-services.d/30-monitoring.sh b/birdnet-pi/rootfs/custom-services.d/30-monitoring.sh
index cf065be70..62d9f9991 100755
--- a/birdnet-pi/rootfs/custom-services.d/30-monitoring.sh
+++ b/birdnet-pi/rootfs/custom-services.d/30-monitoring.sh
@@ -87,8 +87,8 @@ while true; do
 
     # Check service states
     for service in "$srv" "$srv2"; do
-        local state_var="${service}_state"
-        if [[ "${!state_var}" != "active" ]]; then
+        state_var="${service}_state"
+        if [[ "${state_var:-}" != "active" ]]; then
             log_yellow "$(date) INFO: Restarting $service service"
             sudo systemctl restart "$service"
         fi