trying to add a new entry in windows 10 hosts file

Solution 1:

Should I be able to do this?

No. Host files do not contain port numbers.

The hosts file contains lines of text consisting of an IP address in the first text field followed by one or more host names. Each field is separated by white space – tabs are often preferred for historical reasons, but spaces are also used. Comment lines may be included; they are indicated by an octothorpe (#) in the first position of such lines.

Source: hosts (file) - Wikipedia