How to resolve "Domain's DNS record could not be retrieved" in GitHub page creation process?
Solution 1:
If you've recently changed or removed your custom domain and can't access the new URL in your browser, you may need to clear your browser's cache to reach the new custom domain. For more information on clearing your cache, see your browser's help site.
In order to serve the Page, your DNS records must point to GitHub's server. To confirm that your custom domain points to GitHub's servers, use the dig command with your custom domain. The dig command shows you where your custom domain points. For example:
$ dig example.com +nostats +nocomments +nocmd
example.com. 3600 IN A 185.199.108.153
In the example above, example.com points to the IP address 185.199.108.153.
If you configured A records through your DNS provider, your A records must point your custom domain to the following IP addresses:
- 185.199.108.153
- 185.199.109.153
- 185.199.110.153
- 185.199.111.153
- You may see a different IP address, since we serve Pages with a global Content Delivery Network. Use dig username.github.io to see the full resolution path. Note that DNS caching may cause a delay.
- If you're using an A record that points to 192.30.252.153 or 192.30.252.154, you'll need to update your DNS settings for your site to be available over HTTPS or served with a Content Delivery Network. For more information, see "HTTPS errors."
- If you're using an A record that points to 207.97.227.245 or 204.232.175.78, you'll need to update your DNS settings, as we no longer serve Pages directly from those servers.
Source: https://help.github.com/en/articles/troubleshooting-custom-domains