Cover both the www and the bare domain in the certificate on Vercel

Why it matters

The www and bare versions of the domain answer on HTTPS, but one of them is served with a certificate that is not issued for it. Visitors who type or follow that version see a security warning.

The fix

1. Add both the bare domain and the www name to the project under Settings then Domains. Vercel issues a certificate per domain added.
2. Set one to redirect to the other, and set the DNS records Vercel shows for each.

Read the documentation ↗(opens in a new tab)

Related

• Reported by the certificate names and validity window check
• Use a certificate with a standard validity period