try

Jenkinsfile

@@ -103,7 +103,7 @@ node{
 	
 	def imageExpress = stage("Build express preprod")
 	{
-		docker.build("server-express-preprod", "--no-cache --label traefik.enable=true --label traefik.http.routers.server-express-preprod.rule='Host(`api-preprod.foodgame.fr`)' --label traefik.http.services.express_preprod.loadbalancer.server.port=9991 --label traefik.http.routers.server-express-preprod.entrypoints=websecure --label traefik.http.routers.server-express-preprod.tls.certresolver=myresolver  ")
+		docker.build("server-express-preprod", "--no-cache --label traefik.enable=true --label traefik.http.routers.server-express-preprod.rule='Host(`api-preprod.foodgame.fr`)' --label traefik.http.services.express_preprod.loadbalancer.server.port=4000 --label traefik.http.routers.server-express-preprod.entrypoints=websecure --label traefik.http.routers.server-express-preprod.tls.certresolver=myresolver -f express-server/Dockerfile express-server")
 	}
     stage("Run Container express preprod")
 	{

express-server/index.js

@@ -34,14 +34,14 @@ app.use(metricsMiddleware);
 //metrics
 app.use(makeApiMiddleware()); 
 
-app.get("/api", (req, res) => {
-    res.status(200).send("Api Works.");
-  });
+//app.get("/api", (req, res) => {
+   // res.status(200).send("Api Works.");
+  //});
 
-// var corsOptions = {
-//     origin: 'http://example.com',
-//     optionsSuccessStatus: 200 
-//   }
+ var corsOptions = {
+     origin: 'api-preprod.foodgame.fr',
+    optionsSuccessStatus: 200 
+  }
 
 //Définition des CORS Middleware 
 app.use(function(req, res, next) {
@@ -83,7 +83,7 @@ require('./lib/db');
 
 
 //listen for requests 
-const PORT = process.env.PORT || 9991;
+const PORT = process.env.PORT || 4000;
 app.listen(PORT, () => {
     console.log(`Api listen on port ${PORT}.`);
 });