Finally got Astro Go running on Safari in High Sierra (not sure if it's related to the new OS) and all because I want to watch live football on my Macbook.

Don't follow the instructions as it will lead to frustrations and curses. After many tries, I managed to get it working in Safari (High Sierra) -not Chrome (so do advise if you managed to get it working, thanks).

The problem most Macbook users faced or facing is the second part of the instruction to download the plugin (after installing the chrome extension). You will try to click on the button but nothing will happen. If you click the last option to remove the popup and play the video to get back the popup to download the plugin.. the popup will not re-appear. Even if it did, you still won't be able to click it (assuming). This was the instruction given by the author from Astro (who apparently or evidently did not test or retest a fresh setup on more than one Macbook).

Here's what I did and I assume the plugin was not installed previously (as in my case) :
1. Remove the Astro chrome extension (if it was installed earlier).
2. Close all browsers (Chrome and Safari) - not important but why not.
3. Start both browsers again.
4. (Safari) Open the Astro Go website, login, and try to play a video. You should be getting the popup for Chrome extension installation, Plugin installation and "Got It" (or something similar).
5. (Safari) In the popup, click the second option - Plugin installation and the download will start. Once completed, don't do anything anymore in Safari.
6. Switch to Chrome browser.
7. (Chrome) Open the Astro Go website, login, and try to play a video. As like Safari, you will see the popup. Click the first option - Chrome extension installation and follow as per instructions given by Astro.
8. (Macbook) Extract the downloaded plugin and install the package. You should be getting a prompt (IIRC) that installation was successful. For me, I did not need to give additional authorisation (compared to Astro's instruction).
9. Close and start the Safari browser (not sure if I did this).
10. (Safari) Open the Astro Go website, login, and try to play a video. The video should be able to load now (for me at least).
11. If you (like me) successfully managed to get this working.. congratulations but do note on few issues playing video under Safari (not sure if Chrome has the same issue as well.. I never got it working in Chrome).
12. (1st problem) If you try to zoom the browser to get a bigger screen instead of full screen.. the playback will go haywire (nothing playing on screen). Full screen is fine but you won't be able to multitask unless you have a second monitor.
13. (2nd problem) If somehow it stop keep buffering with the irritating red swirling icon, close Safari browser (really Quit/close) and start again, it should work. Refreshing the Safari tab didn't work for me.

Good luck Note: Will update if I have more to add.