Why Messages Fail When the Wrong From Number Is Used

Last updated: April 12, 2026

Last Updated: April 12, 2026

Customer-Facing Guide

What this means

If a workflow or API request tries to send from a number that is not assigned to your Sendblue account, the send can fail even when the rest of the account is healthy.

Common causes

  • A workflow step is still pointing to an old number.

  • An API request is using a number that belongs to another account or workspace.

  • A CRM or automation copied an outdated sending number into the send step.

How to fix it

  1. Open the workflow, automation, or API configuration that is sending the message.

  2. Check which Sendblue numbers are currently assigned to your account.

  3. Update the send step so the from number matches one of your assigned Sendblue numbers.

  4. Retry the send after saving the change.

Good examples

  • +14155550987 — an assigned Sendblue number on your account

  • +14155550988 — another assigned Sendblue number on your account

Bad examples

  • A personal cell number that is not provisioned in Sendblue

  • An old number from a previous workspace or account

  • A blank or malformed from_number field

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