Authenticate a domain in SendGrid

Without domain authentication, SendGrid may force From rewriting or land mail in spam. Agencies should authenticate each client domain they send from.

Steps in SendGrid

1. Settings → Sender Authentication → Authenticate Your Domain.
2. Pick the DNS host if prompted (or “Other”).
3. Enter the root domain (client.com).
4. Leave automated security on unless IT requires custom CNAMEs.
5. Copy all DNS records SendGrid lists.
6. Publish them at the DNS host.
7. Click Verify in SendGrid until status is Verified.

Single Sender vs domain

Method	Use for
Domain authentication	Production client brands
Single Sender Verification	Temporary tests only

Mailgun-style “must have a domain” is stricter; SendGrid allows Single Sender for early tests, but client work should move to domain auth quickly.

Then in EonMailer

1. Connect the API key (guide).
2. Import or add the domain in Deliverability.
3. Re-check readiness until DKIM/SPF pass.
4. Create a verified sender profile on that domain.

Common failures

• Missing one of the DKIM CNAMEs.
• Apex SPF already has too many lookups (include: chain) — flatten or consolidate.
• Verifying www.client.com while sending as client.com — keep identity and From aligned.

Next

• Create a SendGrid API key
• DNS overview