diff --git a/server/index.cjs b/server/index.cjs
index b135b60..a794823 100644
--- a/server/index.cjs
+++ b/server/index.cjs
@@ -443,10 +443,11 @@ function postJson(url, data) {
   })
 }
 
-function computeErpSignature(mercantId, statusCode, nominal, clientId) {
+async function computeErpSignature(mercantId, statusCode, nominal, clientId) {
   try {
     const raw = String(mercantId) + String(statusCode) + String(nominal) + String(clientId)
-    return crypto.createHash('sha512').update(raw).digest('hex')
+    const sign =  crypto.createHash('sha512').update(raw).digest('hex')
+    return sign;
   } catch {
     return ''
   }
@@ -483,13 +484,13 @@ async function notifyERP({ orderId, nominal, mercantId }) {
     logWarn('erp.notify.skip', { orderId, reason: 'missing_mercant_id' })
     return false
   }
-  const signature = computeErpSignature(mId, statusCode, nominal, ERP_CLIENT_ID)
-  // Payload ERP harus flat: { mercant_id, nominal, status_code, signature }
+  const signature = await computeErpSignature(mId, statusCode, nominal, ERP_CLIENT_ID)
+  
   const payload = {
     mercant_id: mId,
     status_code: statusCode,
     nominal: nominal,
-    signature,
+    signature: signature,
   }
   logInfo('erp.notify.start', { orderId, url: ERP_NOTIFICATION_URL })
   try {