Your https://asciinema.org/ website is currently down with error 504 Gateway Time-out . Please, fix it!
Seemed to be temporary hiccup. Seems fine now. Thanks reporting!
[181016-2307 GMT/UTC] Your https://asciinema.org/ website is currently down with error 502 Bad Gateway
Thanks @just4t. Hosting provider had to reboot the machine due to some Intel CPU vulnerability patching, and Docker didn’t start load balancer 
Should be ok now.