how to run the nodejs app without port? currently it is running with port 3005

Hi, 
i have nodejs app with express server. installed correctly on ctrlx Core virtual. showing on side bar, upon click on app it runs on ctrlx like this https://{ip}:3005/project1

But i want to run it without port https://{ip}/project1
how i can do it?
here is code screenshot of code which is running,

Now i change the port to default port 80 . it runs on local system correctly, but when i built its snap and installed on ctrlx core virtual it says: 

404 – Page not found

There is no page available under the path /project1.