Hello, 

Do you have a binding for port 81 set up in IIS for the SmarterMail site? Does your Server meet the minimum system requirements?

This software is not designed to work on a desktop OS, you will want to make sure you are running a server version with a dedicated IP address.  

Thank you

In addition to the potential missing binding, installing SmarterMail on Windows 10 is not recommended due to the client connection count limitation in end-user operating system versions. Windows 10 has a limit on how many client connections can terminate on the machine, and this is quickly reached when using server software as dynamic connections on the backend can hit this limit with little utilization. As such, I recommend you leverage a server operating system for your testing for best results.