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Top 5 Reasons Your SMS Isn’t Being Delivered

This article was published on August 3, 2021
Asian young girl using a mobile phone in downtown, Bokeh city light in background

Texting a global audience can be a bit of a crapshoot. Each country and carrier has their own rules about what type of SMS traffic is allowed, and some countries only allow certain carriers, making it impossible to send a direct (and secure) SMS to certain locations.

If your business is running a global SMS campaign, you've probably noticed the lack of transparency and consistency in the industry. But even if you understand the intricacies of global communication networks, it can be difficult to determine exactly why your SMS is not sending and troubleshoot accordingly.

That's a problem, considering SMS is the most effective way to communicate with many of your customers. In fact, according to Business 2 Community, branded SMS has a 98% open rate and 45% response rate, versus email's 20% open rate and 6% response rate. But messages only get opened if they get sent first.

Wondering why your SMS is not sending? Here are five of the main problems that impact a company's message delivery success rate.

1. Cheap Routes

The bulk SMS industry has long been plagued by shady characters and tactics used to maximize margins. Techniques such as SIM boxes and "grey" routes are illegitimate ways for businesses to connect to the telecom network for a very low cost. With sending bulk SMS, the general rule is that you get what you pay for. SIM boxes, due to their illegality, are shut down by carriers and lead to extremely unpredictable and unreliable message delivery.

Instead of bulk SMS, think scalable SMS. With the right communications provider, you can message your customers and prospects en masse without breaking the bank or compromising data security. It's also much easier to troubleshoot SMS issues when you have a reliable communications platform.

2. Filtered Content

When you're sending messages to countries like China and Saudi Arabia, where the government controls what information citizens are allowed to see, you probably expect to have your content filtered or banned. But they're not the only countries that heavily regulate SMS.

Aside from governments filtering certain types of content, there's also the issue of carrier filters. In Japan, for example, if there's a URL in the body of the message, delivery will fail. Those messages are classified as illegal and either they are discarded completely or the part of the text that's illegal will be removed.

Before starting an SMS initiative, research the specific requirements and restrictions in each destination country to make sure you're set up for obtaining the highest SMS delivery rate possible.

3. Incorrect Sender ID

The Sender ID of a message is the "from" field that appears when someone receives a message. Again, the fragmentation and complexity of the global bulk SMS industry can cause problems for senders, since different countries and carriers have different rules as to what can be displayed in this field.

For example, in the U.S., only numerical Sender IDs are allowed, and all application-to-person messages must be sent from a text short code, whereas in the U.K. they can be alphabetical. If you don't know all the international rules — or have a communications platform that does — an incorrect "from" field could be the reason your SMS is not sending.

4. Message Length

In the U.S. and some other countries, the max SMS length is 160 characters. If you've read points one through three, however, you're realizing by now that nothing is as simple as it seems when you need to troubleshoot SMS issues. Some countries have their own length limits — for example, Brazilian networks only support messages of up to 157 characters.

If your message length is over a country's limit, it will be rejected unless your SMS provider automatically splits it into multiple messages, which could split your link in two, rendering it unclickable.

5. Encoding

Encoding issues might also be the reason your SMS is not sending. At a basic level, encoding determines the possible combination of characters for which characters can be sent. Typically, messages are sent using either unicode, which allows for 70 characters, or using the global standard GSM 3.38 which allows 160 characters.

It's important to know that different carriers and countries require different encoding. Some carriers simply won't deliver messages that are sent in unicode, while others will deliver the message incorrectly. When sending to a new country, always attempt to send in plain text (accents can sometimes show up incorrectly) as opposed to unicode, and always check the Country Specific Guidelines to make sure you aren't missing any important information.

Global SMS is complex, but the extra effort pays off when your brand manages to engage customers via their preferred channel, wherever those customers may be.

Hugh Hopkins
Hugh Hopkins Messaging Product Manager

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