> For the complete documentation index, see [llms.txt](https://docs.limephone.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.limephone.io/troubleshooting/message-delivery-issues.md).

# Message delivery issues

Work out why your texts aren't delivering, why recipients say they never arrived, why you're not receiving texts, and how to keep your messages out of carrier spam filters.

## Outbound messages not delivering

**If you're texting US numbers, check 10DLC registration first.** US carriers filter SMS from unregistered business numbers — this is the single most common cause of undelivered messages to the US. Register your brand and campaign in **Settings → Trust center** (Brands and Campaigns tabs). Until registration is approved, expect heavy filtering on US traffic.

Other causes, usually named in the delivery error:

1. **Unknown or inactive destination number.** The number may be out of service or temporarily deactivated. If you believe it's active, contact support.
2. **Destination handset unavailable.** The recipient's device is off or out of coverage. The carrier may retry for a while, then give up.
3. **Destination number blocked.** The recipient doesn't accept SMS from unknown senders, their mobile plan doesn't include SMS, or their carrier filtered the message as spam.
4. **Destination can't receive the message.** You may be texting a **landline**, or a carrier that can't be reached. Landlines silently can't receive SMS even though the call connects fine.
5. **Flagged for violating carrier guidelines.** The message was filtered — by us or by the receiving carrier — as potential spam. See "Avoiding spam filtering" below. If you believe your messages are compliant, contact support with a brief summary of your business, how you collected the recipients' numbers, and how they consented.
6. **Unknown error.** No specific cause was reported — could be a temporary outage or a connection problem on your end. Check the status page linked from our website, then contact support if it persists.

## Messages show as delivered but never arrive

If your app shows "delivered" but the recipient never got the message, the receiving carrier is likely **soft-blocking**: it accepts the message (so we get a delivery receipt) and then silently discards it. Also check whether the recipient previously replied **STOP** — opted-out contacts won't receive your messages.

Contact support with the date, time, and numbers involved and we'll investigate with the carrier. For US recipients, completing 10DLC registration in **Settings → Trust center** is the strongest fix for soft blocks.

## Not receiving texts on your LimePhone number

1. **Verification codes.** Many services refuse to send OTP/verification codes to virtual numbers. See [Verification codes & virtual numbers](/troubleshooting/verification-codes-and-virtual-numbers.md).
2. **Short codes.** Messages from short codes (5–6 digit sender numbers used for mass texting) are not compatible with all virtual numbers. If one specific service's texts never arrive and they send from a short code, that's the cause.
3. **Recently ported number.** SMS can take 24–48 hours to start working after a port completes. If it's still not working after that window, contact support and we'll escalate to the porting team.

## Avoiding spam filtering

To keep your messages deliverable:

1. **Register for 10DLC** if you text US numbers — **Settings → Trust center**. Unregistered US business texting is filtered by carriers regardless of content.
2. **Get consent first.** Only message people who explicitly agreed to hear from you, and keep a record of that consent (a signed form or a timestamp of the online opt-in).
3. **Offer an opt-out.** Include something like "Reply STOP to unsubscribe" in your first message, and honor opt-outs.
4. **Identify yourself** in the first message ("Hi, this is Ty from Acme Plumbing").
5. **Avoid spam patterns:**
   * No suspicious links — especially shortened URLs.
   * Don't blast identical content to large lists.
   * Keep messages concise; avoid heavy marketing language.
   * Don't send high volumes to contacts you've never messaged before.
   * No prohibited content (cannabis, prescription drugs, phishing, hate speech, harassment, or anything illegal).

If you believe compliant messages are being filtered, contact support with your use case and how your contacts opted in.

## Related pages

* [Contact support](/troubleshooting/contact-support.md)