The goal is to have no blocked text and reach every message recipient in your text message broadcast. This is done by stopping carrier’s blocked text and maximizing throughput. To do this messaging needs to be properly formatted, adhere to broadcast communications standards, and have opt-in/out management.  Great support by your SMS Gateway in managing non-delivery on mobile carriers is critical, when you are having text message delivery issues.

Paying close attention to broadcast management guidelines, and a pre-emptive approach to list management can make the difference.

Blocked text messages can be frustrating. Achieving 100% deliverability may seem impossible. Mobile carriers and end recipients have the most control. Mobile carriers use automated filtering algorithms to guard against SPAM, but legitimate messaging can get blocked unintentionally. Recipients can change their mind about receiving your text messages too. 

Text messaging broadcast management guidelines are stricter than email.

Cold emailing is frowned upon, but it doesn’t strictly break any laws. However, if a company reaches out to a recipient via text without prior consent, that’s a prohibited practice. Guidelines are in place to protect all of us as potential mobile recipients from getting bombarded with non-compliant and SPAM text messages. Recognize that non-compliance may not be SPAM, but it is treated as the same. This means mobile carriers will charge for message delivery, and result in blocked text.

In this article, Swift SMS Gateway breaks down the issue of blocked text, what to look out for, and how to boost deliverability. 

Businesses and SMS Blocked Text

A recipient choosing to block you from sending messages can be confusing. As a sender, you may not be aware, because there’s no firsthand alert informing you about blocked messages, or a blocked text number. You’ll only know that your messages aren’t going through.

Swift SMS Gateway does have analytics that report on blockages. You can request them at

LRN API Lookup

As a first step, proactive broadcast management with LRN (Local Routing Number) Lookup can clean and manage your recipient lists.  Swift SMS Gateway offers this as an essential tool to every business and organization that is using voice and/or text broadcast services. Swift’s LRN service does a live “dip” into the root PSTN (Public Switch Telephone Network) database’s service control point. This determines the destination network of each individual phone number.

Here’s 5 Benefits of Doing LRN Lookups Before You Send: 

  1. Improve reach on your text & voice broadcasts by cleaning bad numbers off your lists.
  2. Reduce your call costs pre-emptively with Swift’s LRN API to better manage broadcasts.
  3. Identify end-carrier networks of recipients.
  4. Sort landline and mobile numbers to know which ones are voice and which are text enabled.
  5. Improve connection quality with location-based routing. 

Don’t waste money sending calls & text to numbers that can’t reach them!

Swift SMS Gateway offers LRN API as an essential tool, giving the most up to  date number status available industry wide. This great service is available to anyone, regardless if you are a current customer, or not. It is used for voice and text services.

A Blocked Text or Restriction – What’s the difference?

Identify whether you have a carrier issue, or an end-user restriction. Accept that carriers have the power to block your messages.

Reasons to believe your business isn’t using SMS appropriately could be any of these examples:

  • Sending too many texts: High frequency is often used as an indicator to flag spam texts.
  • Writing poor content: Badly written texts can also get you on a block list. Using all caps and excessive emojis are key indicators for carriers screening text messages.
  • Contacting non-consenting users: If you buy phone numbers in bulk and send users unwanted text messages, you’re not only violating privacy laws; it’ll also show in user behavior patterns.
  • Using URLs: Especially embedding unbranded URLs in your marketing campaign can get you blocked. The same goes for unbranded shortened links with too many special characters.
  • Unnecessarily long texts: Just like on any other platform, operators want to ensure that you value end users’ time.

Your business may get blocked by SMS recipients for the above reasons. If a notable number of users block your number, and/or opt-out, this alone will flag an issue with the mobile carrier. Some recipients may simply forget they signed up, or get irritated for other reasons. While that can’t be entirely avoided, you can work toward mitigating this risk by implementing some best practices.

  • Don’t risk being yet another unknown sender: Make sure recipients know who they’re receiving messages from.
  • Limit message frequency: At some point, the best offer turns into an unwanted message. Behave like a normal person to prevent opt-out rates from increasing and improve your overall brand reputation.
  • Enable opt-outs: While it may sound counterintuitive from a marketing perspective, giving recipients an easy way out is a key requirement of the Telephone Consumer Protection Act and other privacy laws.
  • Optimize message length: Keep it short and sweet. Aim for 150 characters.
  • Encourage replies: Replying customers will strengthen your reputation among carriers and boost your overall customer engagement. Use polls, surveys and competitions as incentives.

To get the full picture of compliant messaging, check out our comprehensive guide.

Error Statuses and Failed Messages

Every aggregator’s SMS Gateway’s connections to the carriers can only interpret carrier diagnostic codes on cellular delivery, compile them from every operator, and report it to you.

As of 2023, global mobile carriers all have still not standardized message error coding.

While the transit and network protocols in routing have all been standardized across global mobile carriers with all of them supporting IP, the internal network monitoring platforms of carriers are typically proprietary. Ultimately error code delivery diagnostics are handset dependent, with the two major handset platforms being Apple and Android.  Neither are agreeable to share access to baseline operating system access controls and diagnostics to each other, let alone collaborate on a universal standard.

Moreover, while Apple’s mobile OS management strives for universal deployment schedules geographically broadcast across their handset user base, Android cannot accommodate this, because the baseline hardware of the handsets are controlled by multiple manufactures. This demands a subset of OS for handset versions and generational support at a far greater breadth and depth than Apple. So the error codes aren’t going to be the same on every mobile phone. 

However, as this relates to text messaging, SMS is the only universally standardized messaging application preinstalled and configured on every mobile phone – Not even email claims this. As a SMS text message broadcaster, you’ll receive several hints that indicate when message delivery isn’t successful, even when the the exact cause is yet to be determined.

1st Level Success: Get Your Messaging Sent

When you send SMS text messaging, a simple first level of delivery monitoring is needed, to understand the message status at your SMS Gateway such as; Pending, Sent, Failed. If a message clears your SMS aggregator’s gateway, this means it was delivered to the carriers and is SENT.

However, that does not infer that the carrier ultimately delivered that message to the end recipient, regardless of the carrier always charging you and the aggregator for it. If a message is delivered to carriers, it may fail on-route, or be tagged as SPAM, or be rejected by the recipient. All of these will be seen as a SENT status from your aggregator.

If a message is marked FAILED, it hasn’t cleared your SMS Gateway and is not charged. This is typically due to an invalid recipient number, or may be a syntax error in the API call, which typically is not isolated to a single SMS text message. It has cleared your SMS Gateway when it has been accepted by carriers, with a routable recipient number. 

If a message is marked PENDING and appears to be stuck at the SMS Gateway, this is typically a syntax error, or a latency time out network issue and is not charged.

If you are seeing a delivery issue, contact your SMS Gateway support agent. Information needed is timestamp, recipient number(s) to properly investigate. There are many factors that affect delivery performance.

Failure causes require different strategies to address them, from regularly updating subscriber lists and monitoring carrier status updates, to scrubbing your list against DND registries.

2nd Level Success: The Destination Carrier Delivered Your Message

Messaging accepted by carriers does not assume its delivery to recipients. All mobile carriers use SPAM filtering generally in two methods,

Velocity Filtering – Blocks and/or flags transit delivery because the sending number exceeds the accepted message volume per bind. Based on the severity of the violation, it may either proceed to an outright block, or trigger exception reporting to warrant investigation of content with just cause.

Content Filtering – Is a secondary filter that examines the text string of messaging for suspicious, or ill intended means. This includes use of embedded web address using URL shorteners commonly used in phishing schemes, and the use of explicit language, and or illicit means. While the primary reasons for getting text messages blocked is via the carrier or recipient, it’s also good practice to consider other possibilities that could be holding you back.

10DLC Campaign Registration is mandatory in the U.S. Contact your CSP for vetting and approval. 

It could be that your business number simply isn’t verified for mass texting in a channel such as 10DLC. In those instances, it’s best to get support from your provider or other professionals. You won’t be able to address the issue by yourself.

3rd Level Success: Recipients Accept Your Messages

Opt-In/Opt-Out broadcast management of your recipient list is critical. It’s important that recipients not only expect a message from you, but they agree to the purpose of the message and the frequency of it.

General Opt-In Best Practices:

  1. If they permitted you to send appointment reminders only, and you start sending them marketing promotions you have violated their consent.
  2. Do not send any messaging in off-hours. Schedule message broadcasting in reasonable hours, except when directly permitted to do so otherwise. 
  3. Do not abuse recipient’s permission by repeatedly messaging. There is a balance between sending too many times, and not sending enough that they forget about you. 
  4. Clean Opt-Out’s off your broadcast lists. There is a reasonable time permitted to do this in days. 

Opt-Out message backs are monitored by mobile carriers in their mobile originated (MO) filters to look for high volumes of “STOP” replies, which can trigger your sending number to be blocked directly by a mobile carrier.

To learn more about these issues, check out the top 10 reasons why your messages aren’t getting delivered.

Reduce Your Blocked Text With Swift SMS Gateway

At Swift SMS Gateway, we always supply you with the reliable infrastructure necessary for your SMS text message broadcasting while staying on top of compliance requirements. Our flexible support schemes mean you can get the level of service you need for your business.

Whether you’re trying to run a lean organization with basic email support, throw in phone support or benefit from our enterprise package with faster response times — our support team has you covered.

Care to learn more about SMS broadcasting? Level up your text message capabilities and start your Swift SMS Gateway journey by booking a free demo now.