Yes, run a command prompt e.g. Start / Run / cmd
If it returns with no output then it's not finding that port on the server.
If you run:
It will show you all the existing ports which are active and/or bound.
The findstr command searches for a specific text string and if you see no results it means that port isn't in the list or the string was incorrectly typed.
Now if you can connect from one machine however not another it would appear to be a networking issue like you mentioned rather than a server issue.
John A. Booth