Continuous chat loading, all known fixes fail

EDIT after 36+ hours, immediately after posting the below I logged in and found issue had resolved and is working fine…I would still like to know anyones thoughts on what was wrong. If I find out I will post it here for others.
EDIT

Hi, I know that this is a developers forum but I am getting desperate and need to delve into the unknown. I am hoping the experience on this forum may have some idea what is wrong and what can be done.
If anyone knows WHY “rebooting a router” can sometimes fix this issue for others. Then that information would be a good start
The Issue “twitch chat loads continuously”.
To save time the issue is not with a PC but appears to be a network (protocol?) problem, i have done all basic fixes and found that the issue persists across multiple devices and types, multiple twitch accounts, multiple browser types. The issue comes down to the router/network, this has been confirmed on all devices the issue disappears when internet connection is changed to a different router/provider,or, if using a phone, i simply change from wireless to data.
Please note that the network is fine otherwise and working at speed with no buffering issues etc.
The router and NBN ntd device (Australia) was reset.(power cycle) multiple times for long periods.
The issue appeared approx 36 hours ago and is new to this equipment.
I have had no luck with my service provider in locating/understanding the problem.
If anyone has had this issue or even a thought as to what It might be please assist.