First, we have to define what you mean by "access" to a machine (either virtual or physical).
When using putty, I assume you used SSH or simple telnet protocols, and the virtual machine was configured to listen for such requests.
When using a web browser, if not defined, it will automatically try to connect using the HTTP or HTTPS protocols, and that means it is looking for a web server with a web application on that address and port. Web protocols also serve different purposes, and act very differently than SSH for example.
Apache or IIS are examples of such web server infrastructure.
Access to a machine can also be a remote connection with graphical interface (such as windows remote desktop), or any 3rd party app for linux (such as Remmina).
After you define what you actually need and on what protocol you are going to use, you should install and configure a package on that ubuntu machine that will can listen to the port and handle your requests.