Well, I found the culprit... I honestly have no idea how it got there, and I really cant remember placing it there myself...
But in the top <abs> I found a parameter named "gpiport = 7791"...
<abs contexttype="opengear" dblinqport="2222" gpiport="7791" gridsize="10" id="_top" keepalive="true" scroll="true">
I honestly cant remember putting it there myself, but removing it and just using the port 7791 and have DashBoard itself listen to that port worked just fine.
Now I've been working with this DashBoard for years now, so I might've put it there for all I can remember. But I swear to whatever diety you follow, this was working just fine 31st of October, as that was a live hockey game.
However, it did not work the next home game, wich was 16th of November.
Between those two dates, the only thing changing was the IP of the computer (StreamDeck was still set to send to localhost, so should not mean anything), and DashBoard was updated to 8.7.1...
#DashBoard