SendGrid error

Updated 9 October 2026

Short answer

SendGrid requires a verified sender identity: your From address must be verified on its own, or your whole domain authenticated. Sending from an unverified address is one of the most common SendGrid errors. The others are an API key that's wrong or revoked, and messages suppressed because the address bounced before. SendGrid's activity feed shows what happened to each message.

What's the problem

Your app gets an error from SendGrid (often about the From address or the API key), or emails show as dropped, bounced or blocked in SendGrid.

Why it happens

  • The From address isn't a verified sender, and the domain isn't authenticated.
  • The API key is wrong or deleted.
  • The address is on a suppression list after bouncing or unsubscribing.
  • Account limits or an account under review.
  • Missing DNS records for domain authentication.

How to fix it

  1. Find the message in SendGrid's activity feed and read its status and reason.
  2. Verify your sender: authenticate your domain (best) or verify the single From address.
  3. Check the API key in your live environment matches an active key.
  4. Check suppression lists for the recipient if one address never receives mail.
  5. Add the DNS records SendGrid gives you for domain authentication, and confirm they're live.

What Preventionlabs checks

One click runs the full report on your domain. For this problem it shows your email authentication: SPF (and its 10-lookup limit), DMARC and DKIM; whether mail to you must arrive encrypted (MTA-STS) and whether you get reports when it does not; your DNS: nameservers, addresses, DNSSEC, and records pointing at services that no longer exist. It can't see your sending provider's delivery logs, so check bounces there.

Run your free report

Your first report is free, no card needed. Then A$50 a month, up to 10 domains. Read-only: it never changes anything.

Sources

  1. Twilio SendGrid: Sender Identityofficial docsTo maintain the sender reputation and uphold legitimate sending behavior, Twilio requires verified Sender Identities .
  2. Twilio SendGrid: Sender Identityofficial docsYou can verify one or more Sender Identities using either domain authentication or single sender verification.
  3. Twilio SendGrid: Manage bounced messagesofficial docsA repeat bounce occurs when an address has bounced, bounced a second time, then logged to the bounce suppression list, but you ask Twilio to send to this recipient again.

Related

Emails not sending from my website Check whether the email left your site at all, then whether it was rejected or landed in spam. Most failures are missing SPF/DKIM or wrong sending settings. SMTP error SMTP errors start with a code: 4xx means temporary (try again later), 5xx means permanent (fix something first). The text after the code says what. Emails bouncing A bounce means the receiving server rejected the email. Read the bounce message: a bad address, a full mailbox, or an authentication or reputation problem. Mailgun error Most Mailgun problems come from an unverified domain (a daily limit and "sent via" labels), a wrong API key, or sandbox domain sending rules.

Preventionlabs is independent and not affiliated with SendGrid. Product names are used only to describe the problem.

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