Github subdomain configuration don't work

Hi, i have configured cname of my custom subdomain to github account via CNAME record, and the host can’t resolve it. what may i did wrong?

I have recently switched to cloudflare and found problem with reconfiguring my custom subdomain to github page

You mean Github? Thats a Github issue, respectively not so much of an issue but rather a missing configuration. You need to configure that host on Github too.

Basically it seems working now, but it took about 12 hours (i know the dns takes long to reload, but still)

Might have simply been a propagation issue.