I rejected your flag.
There is really no good answer to this, as none of the choices are optimal.
As Robert said, your flag got piggybacked on top of a spam flag. Because we can only take one action for each group of unique, active flags on the post, I rejected it, as spam flags can carry a penalty if acted upon.
So why wasn't this spam?
Well, the answer was from the user who posted the question, asking why their program couldn't connect to a service. I read the cryptic answer ("firewall firewall firewall") to mean that it was a firewall issue on their machine which blocked access to the service.
That makes it "Too Localized" and not spam (hence the "Too Localized" closure from me)
Unfortunately, your flag had to be rejected in the process.
We've also been asked by SE to take a very literal approach to VLQ, NAA, and Spam flags. If a flag is processed as helpful on these posts, then these posts are candidates for being honeypots in the review queue.
It most definitely wasn't an answer, but it wasn't spam, and given the fact that spam flags carry a penalty, and we're supposed to process these literally (and the Spam flag was the heavier of the two, it screams bright red in the mod queue!), I felt the flag had to be rejected. Your flag was an unfortunate side effect.
In an ideal world where your flag was the only one on the post, I would have marked the flag as helpful, and then closed the post as "Too Localized"; the flag was helpful, even though it is an answer to the question (albeit a sparse, and hard-to-decipher one).
It could be a comment, but honestly, given that it invalidates the entire question, it doesn't really matter, what's important is that your flag would have been marked as helpful.