Understanding and Preventing SMS Carrier Filtering (Error 30007)

Overview

Error 30007, known as carrier filtering, indicates that an SMS message you sent was blocked by a mobile carrier. This typically happens when a message is flagged as unwanted, spam-like, or non-compliant with carrier regulations or legal standards. This article explains why filtering occurs, how to prevent it, and the steps to take if you believe your compliant messages are being blocked incorrectly.

What Is Error 30007 – Carrier Filtering?

This error code signifies that a carrier has intercepted your message before it could be delivered to the recipient. Carriers apply these filters to protect consumers from spam, enforce their own messaging policies, and comply with national regulations, such as the A2P 10DLC framework in the United States. Messages are commonly filtered for reasons including:

• Violating a carrier's specific content policies.
• Appearing similar to spam or fraudulent traffic.
• Lacking mandatory compliance elements, such as proof of recipient consent (opt-in) or clear sender identification.

Carriers are increasing enforcement, paying particular attention to traffic that generates consumer complaints due to unclear opt-out instructions or a lack of proper consent.

How to Prevent Messages from Being Filtered

Adhering to the following guidelines will significantly improve your message deliverability and compliance.

Step 1: Manage Consent and Opt-In

Only send messages to contacts who have explicitly agreed to receive them. Every message must clearly identify your business as the sender and include instructions on how to stop receiving messages. When messaging the same contact regularly, you must include these opt-out instructions at least once every 30 days. Use standard language like "Reply STOP to unsubscribe," as creative alternatives may be deemed non-compliant. It is also a best practice to reconfirm opt-in consent every 18 months, especially to account for recycled phone numbers.

Step 2: Select Appropriate Use Cases and Sender Identities

Avoid sending messages for prohibited industries, such as payday loans or cannabis. Do not use multiple phone numbers to distribute similar messages in an attempt to bypass filters (a practice known as "snowshoeing"). Instead, use numbers that are appropriate for your business's geography or specific departments. For international messaging, ensure you use the correct sender type (like a pre-registered short code or alphanumeric sender ID) as required by the destination country's regulations.

Step 3: Craft Compliant Message Content

The content of your message is heavily scrutinized. Avoid using public URL shorteners (e.g., bit.ly); instead, use links from your own branded domain. Do not use links that hide the true destination. Write in clear, professional language and avoid excessive use of emojis, capital letters, or punctuation. Ensure your messages are free of spelling errors and never contain misleading or illegal content.

Step 4: Adhere to Opt-Out and Compliance Rules

Every message must meet core compliance requirements: it must name the sender, provide opt-out instructions, and be sent only to contacts who have given explicit permission.

Step 5: Monitor and Manage Do-Not-Disturb (DND) Status

Regularly process requests from contacts who wish to opt-out. If a message triggers a 30007 error, the contact may be automatically marked as DND within your CRM. You should remove these contacts from your messaging lists.

Best Practices for Higher Deliverability

To further ensure your messages are delivered, use custom short URLs that are associated with your business domain. Limit the number of redirects a link goes through and avoid cloaking the final destination. When possible, use the full URL to maximize transparency. If you are using an A2P 10DLC registration, ensure that any links in your messages originate from the domain associated with that registration.

What to Do If You Believe You Are Being Filtered by Mistake

If you are confident your messages meet all compliance standards but are still receiving Error 30007, you can contact support for a review. Please gather the following information:

• Examples from at least three different contacts within the last seven days that encountered this error.
• The direct link to each contact's profile in the CRM.

To get a contact link:

1. Navigate to the Conversations section of your CRM.
2. Use the search bar to find the contact by name or phone number.
3. Click on the contact's image or name to open their details page.
4. Copy the URL from your browser's address bar. This is the contact link you will provide to support.

Frequently Asked Questions

Why does filtering vary between carriers?

Each mobile carrier uses its own algorithms and criteria to identify unwanted messages. A message blocked by one carrier might be delivered by another based on factors like content, sending volume, and the sender's history.

What should I consider when messaging international numbers?

SMS regulations differ by country. Some nations require specific sender IDs or short codes, and many have industry restrictions. Always check the local guidelines for the country you are messaging.

How can I tell if a contact was marked DND because of a 30007 error?

You can check a contact's status in their conversation history and review delivery error logs. If a contact is on the DND list and previously had messages filtered with this error, the two events are likely related.