NET::ERR_UNSAFE_PORT

NET::ERR_UNSAFE_PORT is an error in Chrome with the description:

Attempting to load an URL with an unsafe port number. These are port numbers that correspond to services, which are not robust to spurious input that may be constructed as a result of an allowed web construct (e.g., HTTP looks a lot like SMTP, so form submission to port 25 is denied).

It is defined in the file

This description is licensed under the Chromium license.