diff --git a/apps/csms/src/index.ts b/apps/csms/src/index.ts
index 870aee0..85b558e 100644
--- a/apps/csms/src/index.ts
+++ b/apps/csms/src/index.ts
@@ -85,6 +85,9 @@ app.get(
   '/ocpp/:chargePointId',
   upgradeWebSocket((c) => {
     const chargePointId = c.req.param('chargePointId')
+    if (!chargePointId) {
+      throw new Error('Missing chargePointId parameter')
+    }
     const connInfo = getConnInfo(c)
     return createOcppHandler(chargePointId, connInfo.remote.address)
   }),