Possibly something in my config, but I've recently got a lot of
"Sorry, something went wrong. Reload?"
I have used this as an alternate: https://nbviewer.jupyter.org/
If github is not working for you well for your notebooks. You can try Kyso by signing up and importing your notebook from Github directly on this page: https://kyso.io/github, or upload it using this page: https://kyso.io/create/study
Disclaimer - I am OP and founder of Kyso
(Obviously this would be for shits 'n giggles, not any serious work).