Telnyx

This guide covers the most common 10DLC failures across brand registration, campaign approval, phone number assignment, and message delivery — with specific error codes, root causes, and fixes.

Quick links: Brand issues · Campaign issues · Number assignment issues · Delivery issues · Carrier-specific issues

Brand registration failures

Brand registration fails when TCR cannot verify your business identity. The identityStatus field on your brand object indicates the result.

Status	Meaning
`VERIFIED`	Brand identity confirmed
`UNVERIFIED`	Verification failed — action required
`VETTED_VERIFIED`	External vetting completed successfully
`SELF_DECLARED`	Sole proprietor — limited verification

Common brand failures and fixes

EIN mismatch — company name doesn't match IRS records

Error: Brand identity verification failed — company name mismatch.Root cause: The companyName you submitted doesn’t match what the IRS has on file for that EIN.Fix:

Look up your exact legal name on the IRS Tax Exempt Organization Search or your incorporation documents
Update your brand with the exact legal name (including suffixes like “Inc.”, “LLC”)
Re-submit for vetting

curl

curl -X PATCH https://api.telnyx.com/v2/10dlc/brand/{brandId} \
  -H "Authorization: Bearer $TELNYX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"companyName": "Exact Legal Name Inc."}'

Address validation failure

Error: Brand address could not be verified.Root cause: The address doesn’t match USPS records, or uses an incomplete format (e.g., missing suite number).Fix:

Verify your address via USPS Address Lookup
Use the exact USPS-standardized format
Include suite/unit numbers if applicable
Update the brand and re-submit

PO Boxes are generally not accepted. Use a physical business address.

Website URL unreachable or doesn't match

Error: Brand website could not be verified.Root cause: TCR checks that the website is live and relates to the registered business. Common issues:

Website is down or returns errors
URL redirects to a different domain
Website content doesn’t match the business name

Fix:

Ensure your website is live and loads without errors
Use the root domain (e.g., https://example.com, not a deep link)
Verify the website clearly identifies your business name
Don’t use placeholder/under-construction pages

Duplicate brand — already registered

Error: A brand with this EIN already exists.Root cause: Your business was already registered with TCR, either by you or another Telnyx account (or through another CSP).Fix:

Check your existing brands: GET /v2/10dlc/brand
If registered under another account, contact Telnyx support to transfer ownership
If registered through another CSP, you can still create campaigns through Telnyx as a secondary CSP

Low vetting score

Error: Brand vetting score too low for desired throughput.Root cause: The third-party vetting partner (Campaign Verify) scored your brand below the threshold for your desired messaging volume.Fix:

Review your brand profile for accuracy — incomplete or inconsistent data lowers scores
Ensure your website, social media, and public records align with your brand information
Request a re-vet after updating information (each vetting attempt has a fee)
See 10DLC Rate Limits for score-to-throughput mapping

Vetting score ranges: 0–24 (low), 25–49 (medium-low), 50–74 (medium), 75–100 (high). Each tier unlocks higher throughput per carrier.

Sole proprietor OTP verification failure

Error: OTP verification timed out or failed.Root cause: The one-time password sent to your registered phone number wasn’t confirmed in time, or the phone number can’t receive SMS.Fix:

Ensure the phone number on file can receive SMS
Request a new OTP and complete verification within the time window
Check that the phone number matches your identity documents
See the Sole Proprietor guide for detailed steps

Check brand status via API

import telnyx

telnyx.api_key = "YOUR_API_KEY"

brand = telnyx.TenDlcBrand.retrieve("BRAND_ID")
print(f"Status: {brand.identityStatus}")
print(f"Entity Type: {brand.entityType}")

if brand.identityStatus == "UNVERIFIED":
    print("⚠ Brand verification failed. Check rejection reason and update brand info.")

Campaign rejection reasons

Campaign rejections happen during carrier review. The rejection reason is delivered via 10DLC Event Notifications webhooks.

Rejection Reason	Common Cause	Fix
Samples don’t match use case	Sample messages describe a different use case than declared	Rewrite samples to match the exact declared use case
Missing opt-out language	No STOP/unsubscribe instructions in samples	Add “Reply STOP to unsubscribe” to every sample
Inadequate opt-in description	Opt-in workflow is vague or missing	Describe the exact opt-in mechanism (web form URL, keyword, etc.)
Prohibited content	SHAFT content (sex, hate, alcohol, firearms, tobacco) or cannabis	Remove prohibited content or apply for special use case approval
Brand not vetted	Campaign submitted before brand vetting completed	Complete brand vetting first
Duplicate campaign	Similar campaign already registered for this brand	Use the existing campaign or differentiate the use case
Insufficient sample messages	Not enough variety in sample messages	Provide 2–5 diverse samples showing different message types

Writing samples that pass review

Match your declared use case exactly

If you registered as “Customer Care,” every sample should be a customer service message:

✅ “Hi Jane, your support ticket #4521 has been resolved. Reply HELP for assistance or STOP to opt out.”

❌ “Flash sale! 50% off today only!” (this is marketing, not customer care)

Include opt-out in every sample

Every sample message should include opt-out instructions:

✅ “Your order #1234 has shipped. Track: https://example.com/track. Reply STOP to unsubscribe.”

Use realistic content — no placeholders

Carriers reject generic or placeholder text:

❌ “This is a test message” ❌ “Hello , this is ”

✅ “Hi Sarah, your appointment at Downtown Clinic is confirmed for March 5 at 2:00 PM. Reply C to confirm or R to reschedule. Reply STOP to opt out.”

Show variety in your samples

Provide 2–5 samples that demonstrate different message types within your use case:

Confirmation messages
Follow-up messages
Status update messages
Opt-in confirmation messages

Resubmitting after rejection

You cannot edit a rejected campaign. Create a new one with corrected information:

Python

import telnyx

telnyx.api_key = "YOUR_API_KEY"

# Create a new campaign with corrected samples
campaign = telnyx.TenDlcCampaign.create(
    brandId="BRAND_ID",
    usecase="CUSTOMER_CARE",
    description="Customer support notifications for order updates and ticket resolution",
    sample1="Hi Jane, your support ticket #4521 has been resolved. Let us know if you need anything else. Reply STOP to opt out.",
    sample2="Your order #8876 is out for delivery and should arrive by 3 PM today. Reply STOP to unsubscribe.",
    messageFlow="Customers opt in via checkbox on our website checkout page at https://example.com/checkout. They can opt out at any time by replying STOP.",
    helpMessage="Reply HELP for support options or visit https://example.com/help",
    optoutMessage="You have been unsubscribed and will no longer receive messages from us."
)

print(f"New campaign ID: {campaign.id}")
print(f"Status: {campaign.campaignStatus}")

Each campaign submission incurs a TCR registration fee (

15 standard /

4 low-volume). Review samples carefully before submitting to avoid repeated fees.

Phone number assignment failures

After campaign approval, you must assign phone numbers to the campaign. Failures typically involve number eligibility or carrier registration issues.

Number not eligible for 10DLC

Error: Phone number is not eligible for 10DLC campaign assignment.Root cause: The number may be:

A toll-free number (use toll-free verification instead)
A short code
Not provisioned for messaging
Already assigned to another campaign

Fix:

Verify the number type: GET /v2/phone_numbers/{id}
Ensure it’s a standard long code (10-digit US number)
Enable messaging on the number if not already configured
Unassign from any existing campaign before reassigning

AT&T registration timeout

Error: Phone number registration with AT&T timed out.Root cause: AT&T’s 10DLC registration system can be slow, especially during high-volume periods. Registration can take up to 7 business days.Fix:

Wait 7 business days before escalating
Check the number’s registration status via webhooks or API
If still pending after 7 days, contact Telnyx support

AT&T processes 10DLC number registrations in batches. Delays of 3–5 business days are normal.

T-Mobile number rejection

Error: T-Mobile rejected the phone number registration.Root cause: T-Mobile applies additional scrutiny to numbers with low-score brands or campaigns flagged for review.Fix:

Ensure your brand vetting score is sufficient
Verify the campaign isn’t flagged or suspended
Try reassigning the number after the campaign is fully approved
Contact Telnyx support if the issue persists

Bulk assignment partial failure

Error: Some numbers in a bulk assignment request failed while others succeeded.Root cause: Mixed eligibility in the batch — some numbers may already be assigned or not eligible.Fix: Check results individually and retry only the failed numbers:

Python

import telnyx
import time

telnyx.api_key = "YOUR_API_KEY"

failed_numbers = ["+12125551234", "+12125555678"]  # Numbers that failed

for number in failed_numbers:
    try:
        # Check current assignment status
        resp = telnyx.PhoneNumber.retrieve(number)
        print(f"{number}: messaging_profile={resp.messaging_profile_id}")
        
        # Retry assignment
        telnyx.TenDlcPhoneNumberCampaign.create(
            phoneNumber=number,
            campaignId="CAMPAIGN_ID"
        )
        print(f"✓ {number} assigned successfully")
    except Exception as e:
        print(f"✗ {number}: {e}")
    time.sleep(1)

Message delivery failures

Even with approved campaigns and assigned numbers, messages can still fail. These are the most common 10DLC-specific delivery errors.

Error Code	Description	Fix
`40300`	Number not registered for 10DLC	Assign the sending number to an approved campaign
`40301`	Campaign suspended	Check campaign status; contact support if unexpected
`40302`	Brand suspended	Review brand status and resolve compliance issues
`40310`	Rate limit exceeded	Reduce sending rate; see 10DLC Rate Limits
`40311`	Daily message limit reached	Wait for daily reset or request higher throughput via vetting
`40320`	Content flagged by carrier	Review message content for SHAFT violations
`40321`	URL blocked by carrier	Remove or replace flagged URLs; use branded short links

Debugging delivery issues

import telnyx
import json

telnyx.api_key = "YOUR_API_KEY"

# Check message detail record for error info
mdr = telnyx.MessageDetailRecord.list(
    direction="outbound",
    phone_number="+12125551234",
    start_date="2026-03-01T00:00:00Z",
    end_date="2026-03-02T00:00:00Z"
)

for record in mdr.data:
    if record.status != "delivered":
        print(f"Message {record.id}")
        print(f"  Status: {record.status}")
        print(f"  Error: {record.errors}")
        print(f"  To: {record.to}")
        print(f"  Sent at: {record.created_at}")

Carrier-specific issues

Each major US carrier handles 10DLC differently. Here are carrier-specific behaviors to be aware of:

AT&T

Issue	Details
Registration delay	3–7 business days for number registration
Content filtering	Aggressive URL filtering; avoid URL shorteners (bit.ly, tinyurl)
Rate limits	Lowest per-campaign limits; vetting score has largest impact
Suspension	Will suspend campaigns with spam complaints without warning

T-Mobile

Issue	Details
Content filtering	Blocks messages with prohibited content patterns
Number reassignment	Requires 24h cooldown when moving numbers between campaigns
Daily limits	Enforces strict daily per-number limits
Opt-out enforcement	Automatically blocks messages to numbers that texted STOP

Verizon

Issue	Details
Registration	Generally fastest registration processing
Content	Less aggressive filtering than AT&T/T-Mobile
Rate limits	More generous throughput at all vetting tiers

Diagnostic checklist

Use this checklist when troubleshooting any 10DLC issue:

Verify brand status

GET /v2/10dlc/brand/{brandId} — confirm identityStatus is VERIFIED or VETTED_VERIFIED

Verify campaign status

GET /v2/10dlc/campaign/{campaignId} — confirm campaignStatus is ACTIVE

Verify number assignment

GET /v2/10dlc/phoneNumberCampaign?phoneNumber={number} — confirm the sending number is assigned to the active campaign

Check event notifications

Review 10DLC webhooks for rejection, suspension, or status change events

Review message detail records

Check MDRs for specific error codes on failed messages

Check rate limits

Compare your sending rate against your campaign throughput limits. Vetting score determines your ceiling.

Get help

If you’ve followed this guide and still have issues:

Support Ticket

Open a support ticket with your brand ID, campaign ID, and error details.

10DLC Status

Check brand, campaign, and number status in Mission Control.

Event Notifications

Set up webhooks to catch status changes in real time.

Rate Limits

Review throughput limits by vetting score tier.

Sending Messages

Messaging Profiles

Short Code

RCS

Hosted Numbers

Opt Outs

Phone Numbers

Toll Free Verification

10 DLC

10DLC Troubleshooting Guide

Brand registration failures

Common brand failures and fixes

Check brand status via API

Campaign rejection reasons

Writing samples that pass review

Resubmitting after rejection

Phone number assignment failures

Message delivery failures

Debugging delivery issues

Carrier-specific issues

AT&T

T-Mobile

Verizon

Diagnostic checklist

Get help

Support Ticket

10DLC Status

Event Notifications

Rate Limits

Sending Messages

Messaging Profiles

Short Code

RCS

Hosted Numbers

Opt Outs

Phone Numbers

Toll Free Verification

10 DLC

​Brand registration failures

​Common brand failures and fixes

​Check brand status via API

​Campaign rejection reasons

​Writing samples that pass review

​Resubmitting after rejection

​Phone number assignment failures

​Message delivery failures

​Debugging delivery issues

​Carrier-specific issues

​AT&T

​T-Mobile

​Verizon

​Diagnostic checklist

​Get help

Support Ticket

10DLC Status

Event Notifications

Rate Limits

Brand registration failures

Common brand failures and fixes

Check brand status via API

Campaign rejection reasons

Writing samples that pass review

Resubmitting after rejection

Phone number assignment failures

Message delivery failures

Debugging delivery issues

Carrier-specific issues

AT&T

T-Mobile

Verizon

Diagnostic checklist

Get help