GitHub Pages: Enable Enforce HTTPS after DNS is healthy. Do not remove validation records while certificates are being issued or renewed.

Source checked 11 August 2026: GitHub Pages official documentation.

Add the domain in GitHub Pages first, then publish the TXT, CNAME or other verification record it displays. Recheck in the same dashboard after DNS propagation.

Source checked 11 August 2026: GitHub Pages official documentation.

Check authoritative DNS, conflicting records, CAA, proxy settings and the host dashboard. DNS caches can delay visible changes even after the authoritative record is correct.

Source checked 11 August 2026: GitHub Pages official documentation.

It can if you change nameservers without recreating MX, SPF, DKIM and DMARC records. Inventory mail records before the move and verify mail independently afterwards.

Source checked 11 August 2026: GitHub Pages official documentation.

Confirm support and the DS-record handoff with both DNS providers. Remove a stale DS record before a nameserver move or signed validation can fail for the whole domain.

Source checked 11 August 2026: GitHub Pages official documentation.

Yes. A restrictive CAA policy can prevent the platform certificate authority from issuing. Compare the platform’s current CA requirements with your CAA records.

Source checked 11 August 2026: GitHub Pages official documentation.

Connect every hostname you intend to serve, choose one primary HTTPS hostname, permanently redirect the alternatives, and make canonicals and sitemaps agree.

Source checked 11 August 2026: GitHub Pages official documentation.

Usually yes. Add the full subdomain in GitHub Pages and publish the platform-provided CNAME or other record without moving the apex unless the official workflow requires it.

Source checked 11 August 2026: GitHub Pages official documentation.

Compare the host’s expected records with authoritative DNS, remove conflicts, check certificate status, test both apex and www, and retain a dated evidence note of every change.

Source checked 11 August 2026: GitHub Pages official documentation.

Lower TTL in advance, attach and verify the hostname where possible, reproduce mail and verification records, change the minimum DNS records, monitor both endpoints, then remove the old service only after expiry of caches.

Source checked 11 August 2026: GitHub Pages official documentation.