Summary
When starting the server, if a port the server tries to use (IE. 19132) is already taken by another program it silently fails. This effects the current version as well as previous versions of the server software.

Steps to reproduce...

1. Run a server using the Dedicated Server or an unofficial server software using the default 19132 port
2. While the other server is running, start the dedicated server
3. Issue happens as it tries to open the port

What I expected to happen...
Normally the server outputs the following:

[INFO] IPv4 supported, port: 19132
[INFO] IPv6 supported, port: 19133

Since this wouldn't be true though, a message of some sort should appear.
A potential message could be "The port [port number] cannot be used. Please make sure no other software is currently using the port."

What actually happened...
The server outputs:

[INFO] IPv4 supported, port: 0
[INFO] IPv6 supported, port: 0

And then stops running without any more cues as to what the issue may be.
Notes...

• The server could potentially ask for a new port, or ask if the user wants to use the default port if the current port is not the default 19132 port.
• I have experienced this issue on Windows, and am currently unsure if Linux is affected.