Common error codes
| Code | Name | Meaning | How to fix |
|---|---|---|---|
| 30001 | Queue overflow | Message queue is full, message could not be queued | Reduce sending volume or spread messages over a longer period |
| 30002 | Account suspended | Your messaging account is suspended | Contact HoopAI support to review account status |
| 30003 | Unreachable destination | The destination number is not reachable (disconnected, out of service) | Verify the phone number is valid and active. Remove invalid numbers from your lists |
| 30004 | Message blocked | The message was blocked by the carrier or recipient | Check message content for spam triggers. Ensure A2P registration is complete |
| 30005 | Unknown destination | The destination number is unknown or improperly formatted | Use E.164 format (+1XXXXXXXXXX). Verify the number exists |
| 30006 | Landline or unreachable | The destination is a landline or cannot receive SMS | Remove landlines from your SMS lists. Use email instead |
| 30007 | Carrier filtering | The carrier filtered/blocked your message as spam | Register for A2P 10DLC, improve message content, reduce send frequency. See section below |
| 30008 | Unknown error | An unknown delivery error occurred | Retry the message. If persistent, contact support |
| 30009 | Missing segment | A multi-part message had a missing segment | Shorten your message or retry |
| 30010 | Message price exceeds max | Message cost exceeds account limit | Add funds to your wallet or increase the spending limit |
Carrier filtering (30007) — deep dive
Error 30007 is the most common SMS delivery failure. It means the carrier blocked your message as suspected spam.Common causes
- No A2P 10DLC registration — local US numbers without A2P registration are heavily filtered
- Content triggers — messages containing “free,” shortened URLs (bit.ly), or excessive caps
- High opt-out rates — too many recipients replying STOP
- Volume spikes — sudden increase in sending volume triggers carrier filters
- No opt-in consent — sending to contacts who did not opt in
How to fix
- Complete A2P 10DLC registration — this is the single most impactful step. See A2P registration
- Use toll-free numbers with toll-free verification for higher throughput
- Clean your contact list — remove invalid numbers, unsubscribes, and inactive contacts
- Avoid spam trigger words — do not use ALL CAPS, excessive punctuation, or URL shorteners
- Warm up sending volume — start low and gradually increase daily volume
- Include opt-out language — always include “Reply STOP to unsubscribe”
A2P registration errors
| Error | Meaning | Fix |
|---|---|---|
| Registration pending | Your A2P campaign is awaiting carrier approval | Wait for approval (can take 1–4 weeks). Check status in Settings |
| Registration rejected | Your A2P campaign was rejected | Review rejection reason, update your campaign details, and resubmit |
| Brand not verified | Your business brand has not been verified | Complete brand verification with EIN/tax ID documentation |
| Campaign suspended | Your messaging campaign was suspended for violations | Contact support, review compliance, and appeal |
Blacklist and opt-out errors
| Error | Meaning | Fix | |
|---|---|---|---|
| 21610 | Contact has opted out (replied STOP) | Do not message this contact. They must reply START to re-opt-in | |
| 21611 | Number is on the platform blacklist | The number has been flagged. Contact support for review | |
| 21614 | Invalid “To” number | The recipient number is not a valid phone number | Verify and correct the number format |
| 21612 | Invalid “From” number | Your sending number is not valid or configured | Check that the number is active in Settings → Phone Numbers |
Rate limit errors
| Error | Meaning | Fix |
|---|---|---|
| Message rate limit exceeded | You are sending too many messages per second | Slow down your sending rate. Add waits between messages in workflows |
| Daily limit reached | You have hit the daily sending cap for your number | Wait until the next day or use additional numbers to distribute volume |
| Queue timeout | Message sat in queue too long without being sent | Reduce volume or contact support about capacity |
Troubleshooting steps
Check the error code
Go to Conversations and find the failed message. Click the error icon to see the specific error code.
Verify the number
Confirm the recipient’s phone number is valid, properly formatted (E.164), and not a landline.
Check A2P registration
Go to Settings → Phone Numbers → A2P Registration and verify your campaign status is Approved.
Review message content
Remove spam trigger words, URL shorteners, and excessive formatting. Keep messages conversational.
Check opt-out status
Verify the contact has not opted out (DND status). Go to the contact record and check the DND settings.