Think I got my answer already. Hub Sports Arena will cease transmission on 28 December 2018. This impacts all StarHub TV customers as well. So I presume it will no longer be available on any platform. It is a pity though.
See following link :
I sincerely apologize for any inconvenience caused.
Do note that if it works on StarHub Go, it should work on StarHub Go Streaming Box too, as they run on the same app. However, if you are unable to watch it on StarHub Streaming Go Box, it probably has something to do with the Value-Added Service.
If possible, kindly provide screenshots of this error for us to raise this issue to the relevant team to look into it. Thank you.
From what i know Starhub Go App is not applicable to most Android TV box other than this Go Streaming box which is also Android TV box.
Another point is that Starhub Go App on mobile is different from Android TV box as both are on different platforms.
Starhub Go Streaming Box is classified as OEM > Android TV - Starhub Go Streaming Box
As like many other OEM version there may have some limitations and it is brand new.
Features could be added in future via updates on firmware, where applicable.
Also Toggle App is not available yet as stated > Starhub Go Streaming Box - point 17
It is stated at "Live" channels supported are listed > Here!
So it may seem that Sports channels are not in the list.
Maybe you could go thru to compare the differences in Channels available in this Go Streaming Box and Starhub Go App on mobile/website.
Do note that this Starhub Go Streaming Box do have Chromecast built-in.
Maybe you could try to see if you can and able to cast content from your mobile to TV via Starhub Go Streaming box.
Please note that i do not have this Go Streaming Box so would be based on theory and research that i come across.