> ## Documentation Index
> Fetch the complete documentation index at: https://help.withallo.com/llms.txt
> Use this file to discover all available pages before exploring further.

# SMS troubleshooting

> Fix texts that won't send, aren't delivered, or aren't received

<iframe src="https://www.youtube.com/embed/G-3eOQ8ygs4" title="How to register for 10DLC and get your US texts delivered on Allo" frameborder="0" className="w-full aspect-video rounded-xl" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen />

Work through this page top to bottom: most SMS issues come down to compliance registration, number type, or a temporary connection problem.

## I can't send any SMS

<AccordionGroup>
  <Accordion title="US number: is your 10DLC registration approved?">
    Sending SMS from a US number legally requires an approved 10DLC brand and campaign. Until it's approved, carriers block every outbound text.

    * Register under **Settings > Compliance** (one-time \$24 fee, about 5 minutes)
    * Approval typically takes a few business days
    * Once approved, texting is fully conversational, including images and files (MMS)

    [Set up texting](/en/phone-numbers/sms-setup)
  </Accordion>

  <Accordion title="Canadian number: texting US contacts?">
    Canadian numbers can text other Canadian numbers without registration. To text **US numbers**, your 10DLC brand must be approved first. If your texts to the US are blocked, check your compliance status under **Settings > Compliance**.
  </Accordion>

  <Accordion title="French number: are you on a mobile number with a Sender ID need?">
    French regulation doesn't allow automated SMS from a mobile number. For notification-style messages under your company name, register a **Sender ID**, approved in about 48 hours. Daily sending limits are listed on [SMS & messaging](/en/phone-numbers/sms-overview). See [Set up texting](/en/phone-numbers/sms-setup) and [SMS in France](/en/phone-numbers/sms-france).
  </Accordion>

  <Accordion title="Starter plan?">
    The Starter plan receives SMS but cannot send. Sending requires the Business plan.
  </Accordion>
</AccordionGroup>

## Only one of my numbers can text

If you registered 10DLC as a **Sole Proprietor**, only one number can be linked to your campaign. That's a carrier rule, not an Allo limit.

* To enable texting on additional numbers, [contact support](/en/support/contact): we reset your brand and campaign so you can re-submit as a **Private Company**, which supports multiple numbers
* Adding a new number to an existing company campaign doesn't require a new form: ask support to link it, SMS is enabled in 1 to 2 hours

## A message shows "Failed" in the app

A failed status usually means the message never reached our servers, most often because of a connection drop at the moment of sending.

1. Check your internet connection
2. Tap the message to see the error reason
3. Send it again

If the recipient's carrier rejected the message (for example a file too large), the error reason will say so.

## MMS (images and files) won't send

* MMS works on US and Canadian numbers once 10DLC is approved
* Keep attachments under **1 MB**: most carriers reject anything larger
* PDFs are poorly supported by carriers: send a link (Google Drive, Dropbox) or convert to a JPG/PNG under 1 MB
* French numbers can't send or receive MMS: French telecom regulation blocks MMS on virtual numbers, whatever the provider

## I'm not receiving SMS

<AccordionGroup>
  <Accordion title="Recently ported your number?">
    After a port, SMS can take up to 48 hours to flow normally. If your ported number still can't receive texts after that, [contact support](/en/support/contact): a routing adjustment on our side usually fixes it within hours.
  </Accordion>

  <Accordion title="Number shows as VoIP somewhere?">
    That's expected: Allo is a VoIP platform, so lookup tools classify Allo numbers as VoIP. It doesn't prevent SMS. But some third-party services refuse to send verification codes to VoIP numbers, which is why [Allo numbers can't reliably receive OTP codes](/en/phone-numbers/understanding-allo-number).
  </Accordion>

  <Accordion title="Notifications missing but SMS visible in the app?">
    The SMS arrived but the push notification didn't. Check notification permissions for Allo on your device, and see [Common issues](/en/support/common-issues#app-issues).
  </Accordion>
</AccordionGroup>

## Still stuck?

[Contact support](/en/support/contact) with the sending number, the recipient number, and the approximate time of the message. We can trace each message on the carrier side.