A few things:
1. Satellite internet is not really made for streaming TV online. The inherent latency causes problems with some video servers.
2. Standard definition programming or less might be ok, but it only gets worse with higher resolution programs that require a faster ping rate than satellite can provide.
3. A one-hour HD program is about 3-5GB and will eat your plan data like there's no tomorrow.
4. Putting your satellite TV box on the internet will also eat a lot of data as it defaults to that for many of the functions, like guide data, etc.
Sorry to hear you are having trouble streaming HBO Go. As a GoT fan myself, I know this year is big, so all the more reason to get this working for you. When you try to stream HBO Go today, what device are you using?
I can tell you that my experience with HBO Go is touch and go, no pun intended. I don't normally use HBO Go, but when I have it's worked fairly well during the day and late at night, but in the evenings, when most people are online, I saw some buffering. And, unfortunately, there's no way to manually adjust the definition, so there's no way to reduce the amount of bandwidth needed for the streaming. This was mostly using a Windows 10 laptop, though I did try it a few times on a Windows 10 desktop, including just now, with the same results.
One thing I'm not sure of, though, is your HBO subscription with Dish due to the carrier dispute. If it's not active, as in an active HBO subscription, HBO Go will likely not work for you, as your Dish sign on credentials may not show an active subscription. The best thing you can do is just try it. It only takes a few minutes to do it through the HBO Go site. You'll have to choose Dish from the provider's list pull down, then sign in using your Dish credentials. If it doesn't work, you'll know. And, if that's the case, you'll have to look into HBO Now, which you have to pay for.
As for how well HBO Now works with HughesNet, I can't tell you, but it's likely that it's similar to HBO Go. In other words, there are no guarantees regarding buffering, as it appears that HBO Now doesn't allow manual adjustment of definition, either.
The interesting thing here, is that I watched a few seasons leading up to Season 7 via HBO Go on my Verizon iPhone, using LTE. It still buffered at least once per hour(-ish) show despite having full signal strength and no loss in data speed.
Goes to show that: Sometimes, it's just not the network. Sometimes it's the provider. The network is just easier to blame.
I ought to try it on my Tracfone using HughesNet's WiFi. It looks like HBO's Go app for Android phones is a glitchy train wreck, so I'll try it with out the app, just to see what happens. And, I'll try it with the app, as well. The reason for this is that I'm wondering if it's an adaptive stream. Granted, watching it on a 5.5" screen isn't exactly what I would want to do, and I don't have to as I have HBO with my DirecTV subscription, but it might be interesting to find out how it works.
If it's not too glitchy, either with or without using the app, I might try it with my phone's data, which is via Verizon's network (it's a CDMA/LTE Tracfone).
Well, I had no issues. I tried it with both my desktop computer and my phone, with which I had to use the app. The phone was also connected via WiFi, whereas the desktop is connected via ethernet cable. I even left the Video Data Saver on. No buffering. But, this is around 8PM. It might be a bit more congested later, like it was last night, when it buffered a little, even with the Video Data Saver paused.
I also tried it with my phone while using the phone's data, and once I found a place in my house in which I could get a decent signal it worked flawlessly.
So, at least for me, it works just fine when HughesNet's network isn't heavily loaded. But, as always, results will vary. Then again, I wouldn't do this on a regular basis, as it chews through data, though GOT might very well be the one program for which burning through that data would be worth it. And, one can always buy more.
This is just a thought, but PlayOn Cloud allows you to stream shows from HBO Now, as well as other sources, to the cloud. Those programs/films are then converted to an .mp4 file, which you can then download and watch whenever you want. There's no buffering with that, as you're watching from an already downloaded file. There are others on here who use PlayOn Cloud that can probably tell you more about it, but it might be something to consider, especially since, once the files are downloaded, they don't expire, though they only sit in the cloud for seven days for you to download them.
It's just another option, but for we who don't have much daytime data, and want to avoid buffering, it's a pretty good one.