diff --git a/src/components/backend-core/src/microservice-proxy.ts b/src/components/backend-core/src/microservice-proxy.ts
index a37ec9b6..75c4e01b 100644
--- a/src/components/backend-core/src/microservice-proxy.ts
+++ b/src/components/backend-core/src/microservice-proxy.ts
@@ -766,7 +766,8 @@ async function microserviceTunnelSelfTestResponse(service: MicroserviceConfig):
   const bodyRecord = isPlainRecord(body) ? body : {};
   const hasRequestId = typeof bodyRecord.requestId === "string" && bodyRecord.requestId.length > 0;
   const hasStage = typeof bodyRecord.stage === "string" && bodyRecord.stage.length > 0;
-  const ok = response.status === 502 && hasRequestId && hasStage && headers.requestId === bodyRecord.requestId;
+  const expectedStatus = response.status === 502 || response.status === 504;
+  const ok = expectedStatus && hasRequestId && hasStage && headers.requestId === bodyRecord.requestId;
   return jsonResponse({
     ok,
     serviceId: service.id,
@@ -775,7 +776,7 @@ async function microserviceTunnelSelfTestResponse(service: MicroserviceConfig):
     expectedFailure: true,
     status: response.status,
     checks: {
-      expectedStatus: response.status === 502,
+      expectedStatus,
       bodyHasRequestId: hasRequestId,
       bodyHasStage: hasStage,
       headerHasRequestId: typeof headers.requestId === "string" && headers.requestId.length > 0,