I was half on to writing something IP related like Hosts entries and going to suggest listening to the wire, which would have pointed to the error.
But the manual connection stopped me ;-)

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>(it's deja vu all over again!) ;)
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>I got it!
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>It turns out they had McAfee running on this PC (which should not have been). I uninstalled it and can now connect, so I guess that must have had the firewall on and was blocking my program.