This message caught my attention because I saw the verb apparently in the first position in a Hauptsatz, it's an error message that is displayed when you lose connection to a game. I know the conjugated verb in a Hauptsatz is in position 2, so there must be something omitted here, i reckon? Also, i was wondering if you even can use "Verbindung" here without it's article? Maybe this message is ungrammatical? I appreciate your help.
I think, this is as a rather direct translation for the English "Couldn't establish connection". I guess, what is omitted here is "The computer..."/"Der Computer...", "The program..."/"Das Programm..." or similar. Regarding the missing article, this is most probably due to the translation. Messages in computer software are frequently shortened in such a way.
German is a topic-drop language. You can say sentences like:
- Weiß ich nicht. = Das weiß ich nicht.
- Komme heute nicht zum Training. = Ich komme heute nicht zum Training.
If it is clear from the context, you can leave out the thing that is in the position before the verb. That is what is happening here, although admittedly it is not 100% clear whether the thing left out is an "ich" or some third-person subject like "das Programm", "der Client"; it makes no difference in meaning.
As for the missing article, that is just headline language; just like in English, articles can be left out in headlines. This was likely directly translated from "could not establish connection".