If you've built a GHL system, set up your workflows, connected Twilio, and then discovered that SMS just isn't sending — A2P registration is almost certainly the problem. Most people don't know it exists until the system is done and they're wondering why nothing is working.
This guide covers what A2P 10DLC is, what carriers actually check, and the specific mistakes that cause rejections — so you can avoid them.
What A2P 10DLC Actually Is
A2P stands for Application-to-Person. 10DLC stands for 10-Digit Long Code. Together, A2P 10DLC is the US carrier registration system that governs how businesses send SMS messages to customers.
Before A2P 10DLC, anyone could buy a phone number and blast SMS messages to anyone. Carriers cracked down because of spam. Now, any business sending automated SMS in the US needs to register their brand, their use case, and their messaging content with the carriers before messages will deliver reliably.
Without registration, your messages either don't deliver at all or deliver at extremely low rates. This applies regardless of which platform you're using — GHL, Twilio directly, any other provider.
Important: A2P 10DLC is a US requirement. If you're sending SMS to UK, UAE, or other international numbers, different rules apply — but US numbers require this registration without exception.
The Three Things You Need to Register
A2P registration has three components, and all three need to be approved before your messages send reliably:
1. Brand Registration
This is your business identity. You register the company name, EIN (Employer Identification Number), business type, address, website, and contact details. This tells carriers who is sending the messages.
2. Campaign Registration
This is your use case — what you're sending SMS messages about. There are different campaign types: marketing, customer care, 2FA, notifications, and others. Most service businesses register under "Mixed" or a specific use case like "Appointment Reminders."
3. Phone Number Association
Once your brand and campaign are approved, you associate your Twilio phone numbers with the campaign. This links your numbers to your registered use case.
Why Applications Get Rejected
After handling A2P for multiple clients, these are the actual reasons applications get rejected:
Opt-in language mismatch
This is the most common rejection reason. Your A2P application includes sample opt-in language — the exact text that appears on your form when someone provides their phone number. If the live form on your website shows different language than what you submitted, carriers reject it.
The fix: screenshot your actual form before submitting. Copy the opt-in text exactly. Submit that exact text. Do not update the form after submission without updating the application.
The trap: You build the GHL form, submit A2P, then update the form to look nicer and accidentally change the opt-in language. Instant rejection. Lock the opt-in language before submitting and don't touch it.
Missing or weak privacy policy
Your website must have a privacy policy that explicitly mentions SMS communications. "We may contact you by phone" is not enough. It needs to specifically say you may send SMS messages, what they'll contain, and how to opt out.
Required privacy policy language for SMS: something like "By providing your phone number, you agree to receive SMS messages from [Company Name] related to [purpose]. Message and data rates may apply. Reply STOP to opt out at any time."
No terms of service
Carriers want to see a terms of service page on your website. It doesn't need to be complex — but it needs to exist and be linked from the footer.
Opt-in language not on the form
The form that collects phone numbers must have opt-in language visible before submission. It's not enough to have it in your privacy policy — it needs to be on the form itself, near the phone number field, before the submit button.
Standard opt-in text: "By submitting this form, you agree to receive SMS messages from [Company Name]. Reply STOP to opt out. Message rates may apply."
Business type mismatch
The business type in your brand registration must match your EIN registration. If your EIN is registered as an LLC but you select "Sole Proprietor" in A2P, it gets rejected.
Sample messages that don't match use case
When you register a campaign, you provide sample messages. These must match the campaign type you selected. If you register for "Appointment Reminders" but your sample messages are promotional — "Special offer this week only!" — the campaign gets rejected.
Sample messages should be plain and specific to the use case. For appointment reminders: "Hi [Name], this is a reminder of your appointment with [Company] on [Date] at [Time]. Reply STOP to opt out." That's exactly what carriers want to see.
The Checklist Before You Submit
Go through this before submitting any A2P application:
- Business registered with EIN — business type matches what you'll enter in A2P
- Website live and accessible
- Privacy policy page — explicitly mentions SMS communications and opt-out method
- Terms of service page — exists and is linked from footer
- GHL form — has opt-in language near the phone number field, before submit button
- Screenshot the opt-in language — this is what you'll paste into the A2P application exactly
- Sample messages ready — specific to your use case, include opt-out language
- EIN ready — you'll need this for brand registration
- Authorised representative details — name, title, email, phone of the person responsible for the account
Timeline and What to Expect
A2P registration is not instant. Here's the realistic timeline:
- Brand registration: 1-3 business days for initial review
- Campaign registration: 3-7 business days typically, can take up to 2-3 weeks
- Number association: Usually same day once campaign is approved
The practical implication: submit A2P registration before you build the SMS sequences. Don't build a complete system and then discover you have a 2-3 week wait before SMS works. Submit early, build while you wait.
What Happens If You Get Rejected
Rejection isn't permanent. You can resubmit after addressing the issue. The rejection notice usually tells you why — read it carefully. The most common fix is updating the opt-in language on the live form to match the application exactly, or adding the required privacy policy language.
If you've been rejected twice, go through the full checklist again from scratch. Don't just fix the specific rejection reason — verify every requirement is met before resubmitting.
Need A2P handled for you?
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Book a Free Call →Summary
- Submit A2P before building SMS sequences — approval takes weeks
- Opt-in language on the live form must exactly match the application
- Privacy policy must explicitly mention SMS communications
- Terms of service page must exist
- Business type must match EIN registration
- Sample messages must match the campaign type selected
- Lock the form opt-in language before submitting — don't change it after