commented on the section with CORS

src/metrics.gateway.ts

@@ -4,11 +4,12 @@ import { PrometheusService } from './prometheus.service';
 import { Logger } from '@nestjs/common';
 
 @WebSocketGateway({
+    /* 
      cors: {
          origin: '*', // В production укажите конкретные домены
          methods: ['GET', 'POST'],
          credentials: true
-    },
+     }, */
     namespace: '/api/metrics-ws'
 })
 export class MetricsGateway implements OnGatewayInit, OnGatewayConnection, OnGatewayDisconnect {