socket.server is not a constructor

The error "socket.server is not a constructor" usually means that you are trying to use the `server` property of a `socket` object as a constructor, which is not allowed.

Without more context, it's difficult to provide a specific solution. However, here are a few possible reasons and solutions:

- You might be trying to use `socket.server` instead of `socket.io` to create a server. In that case, you should use `const io = require('socket.io')(server)` to create a new `socket.io` instance and pass it the `server` object.

- You might have a typo in your code, and you're trying to call `socket.server()` instead of `new Server()` (assuming you're trying to create a new `Server` object).

- It's possible that you're trying to use `socket.server` outside of the scope of a `socket` connection, which means that `socket` is `undefined`. Make sure that you're using `socket.server` within the correct context.

Overall, it's important to carefully check your code and make sure that you're using the correct syntax and objects.