SendGrid · api · fg-0421

SendGrid returns 202 but a recipient never gets mail because the address is suppressed

202 Accepted, then a dropped event instead of delivered

Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100

Cause

Addresses on the bounce, invalid, spam report, global unsubscribe, or group unsubscribe lists are dropped after the API accepts the request, and each attempt still uses a credit. Bounces and spam reports keep suppressing until removed.

Fix

Check the suppression lists for the address, remove it only when the user has fixed or confirmed it, and for required transactional mail set bypass flags narrowly.

Apply

GET /v3/suppression/bounces/{email}  then  DELETE /v3/suppression/bounces/{email}

Affects: SendGrid v3 Mail Send and Suppressions API, as of 2026-10

Sources

https://www.twilio.com/docs/sendgrid/ui/sending-email/index-suppressions

Have your agent know this before it fails

claude mcp add --transport http footgun https://getfootgun.com/api/mcp