Domain does not resolve to the GitHub Pages server

I configured a custom domain for the site sime time ago and everything was fine. After a while the site doesn’t work and I have the following message on Settings tab: “Domain does not resolve to the GitHub Pages server. For more information, see articles/setting-up-a-custom-domain-with-github-pages/”. However, I checked the records and seems a still have the right values. You can see them using the follwoing links:

What’s the problem?

Hmm, it started to work although it didn’t work several days. Close this, please.