DISE Server's web interface is accessible through port 80 (HTTP), or 443 (if SSL is enabled), just like a regular web server. HTTP/HTTPS traffic needs to be allowed through the server firewall(s) in order for the web interface to be accessible from the outside. In addition, a public IP access to DISE Server is required if players and users are to connect to it over the internet.
If there is already a web server installed on the server, such as IIS or Apache, make sure that you either stop these services or rebind them to a port other than 80/443. Then, restart the DISE Server service.
Please check the results from this page: Real-Time Web Test - Does your browser support WebSockets? DISE Server tunnels websockets through port 80 (or port 443 if SSL is enabled). Reasons that sockets may still be unable to connect are
In order to reset the admin password to "diseserver", please do the following:
785C9AC9FABA0ADD03C3CE975CC7505D7D1098676ED7AF2E36
admin / diseserver