In the world of read receipts, emoji reactions, and “someone is typing,” not getting your text message delivered is frustrating — especially when you don’t know why it happened.
Whether it’s a technical glitch, an issue with your recipient’s device, or a problem on your end, understanding the root cause can save time and prevent miscommunication. Let’s dive into the common reasons your message might not have made it through.
Why does my message not say delivered?
Your text message may not say ‘delivered’ due to several reasons. The recipient’s phone might be switched off or out of service range. The recipient might have blocked your number. Or the carrier might be experiencing technical difficulties. It’s also possible you’ve entered an incorrect or non-working phone number.
We’ve seen them all and will share what we’ve learned in this post.
Here are 14 reasons why your message didn’t get delivered.
1. Your message was flagged as spam by the recipient’s carrier
With the rise of business text messaging, carriers have started protecting their subscribers from SMS spam. Similar to how your email provider moves messages they think are suspicious to the Spam folder, your mobile carrier does the same. Except those text messages don’t get delivered to you at all. They simply get filtered out by your carrier.
When you’re texting someone for the first time, keep in mind that your message can get filtered out. This happens when something in your message raises a flag for the recipient’s carrier.
While many carriers have their own guidelines and methods for fighting spam, some principles are universally followed.
Here are some of the common reasons your number may be marked as spam:
- You’re sending suspicious links, especially if you’re using a URL shortener like bit.ly or TinyURL.
- You’re sending a lot of messages with the same content.
- You’re sending overly long messages. Every SMS segment is 160 characters long, so if you’re sending an essay, that’ll raise a red flag for the receiving carrier.
- You’re using all caps in your messages like “SIGN UP NOW FOR FREE.” This looks suspicious (and isn’t effective).
If you’re texting from a virtual phone solution, your text may also get filtered by your recipient’s carrier based on guidelines pushed for by the large US cell companies. The major US cell carriers recommended that anyone with a local (non-toll-free) number and using a virtual phone solution get verified through The Campaign Registry, a third-party organization handpicked by these carriers. If you haven’t already registered and use OpenPhone, you can get verified through the US carrier registration form.
💡 Looking for a more reliable service provider? Check out our guide to the best texting services.
2. You need a different type of phone number
There are two types of messaging — A2P (application-to-person) and P2P (person-to-person). These types require different kinds of phone numbers.
If your business sends messages to your customers, there’s a chance you’re engaging in A2P 10DLC messaging. This includes texts like appointment reminders, billing confirmations, and other transactional texts sent through an application like OpenPhone.
If you have a personal relationship with your customers and are not sending templated or automated messages, you’re likely engaging in P2P messaging. This means you’re texting them like you would text a friend.
If A2P describes your use case best, you need to make sure you have an appropriate type of phone number for it. Short codes and certain local numbers approved for high-volume messaging (known as 10DLC or 10-digit long code) will work here. Using a regular local phone number to send hundreds or thousands of messages in a short time span will get your messages blocked by the carriers, especially if you’re not compliant with 10DLC.
If P2P describes your use case, you’ve got nothing to worry about. As long as you don’t send hundreds of messages in a short span of time, you’ll be all set.
If you’re looking to send a high volume of messages, send us a note, and we’ll be happy to help find a number type that suits your needs.
3. You’re sending too many messages
Similar to the point above, if you’re sending a lot of text messages or doing SMS blasts, your messages might be caught in the spam filter. Many networks have an anti-flooding filter, which limits the number of messages a recipient can receive within a specific timeframe to prevent spam.
There are also guidelines around how many messages you can send, depending on the type of number you’re using.
Phone numbers designated for P2P traffic (typically your local numbers on a cell phone) are generally only allowed to send 1 message per second. There should also be a fairly even one-to-one balance of sending and receiving messages. If you’re sending 300 messages but only getting 10 responses, it raises a red flag and can lead to your messages being blocked.
4. The recipient opted out of messages
Most SMS platforms have a built-in system that allows recipients to opt out of receiving messages.
For example, in OpenPhone, if someone replies with “STOP,” they will no longer be eligible to receive texts from you. Unless they opt back in, you won’t be able to message them.
5. The recipient blocked or filtered out your phone number
While this is rare, it happens. If the recipient blocks your phone number from contacting them, your message won’t be delivered. Similarly, some carriers or apps may filter your messages as spam, preventing delivery. If you don’t see a ‘Delivered’ or ‘Read’ notification, this is a likely explanation.
6. The message contained illegal or illicit content
If you’re sending messages with illicit or illegal content, such as adult content, references to drugs, or anything referring to criminal activity, they can get blocked by the receiving carrier.
CTIA (Cellular Telecommunications and Internet Association) is a regulatory body that enforces guidelines for SMS messages. You must ensure that the content of the messages you send complies with all applicable laws where the message recipient is located.
7. You’re texting a landline
Despite all advances in technology, there are still phones connected with wires. They don’t support messaging and are limited to calls only. If you’re texting a landline, your message is most likely not getting delivered.
8. Network problems with the recipient’s carrier
While not that common an issue, the recipient’s carrier network sometimes has problems that can halt delivery.
These issues may include temporary outages, network congestion during peak times, or routing errors. In these cases, messages may be delayed or fail to deliver until the carrier resolves the problem.
9. Billing issue on the recipient’s carrier side
Although this rarely happens, it’s possible that you’re texting someone on a pre-paid plan who has an outstanding balance on their account. Many carriers offering pre-paid plans block these accounts from receiving messages until the balance is paid.
Their number may also be temporarily unavailable if they’re in the process of changing their mobile contract to another provider.
10. Recipient reported your message to their carrier
If you’ve followed all the tips above and still had a message undelivered, there’s a chance a recipient reported your message to their carrier. It’s also possible they reported a message that looked similar to the one you sent, so their carrier preemptively blocked your message.
11. You’ve entered a wrong number or the number is incorrectly formatted
You’d be surprised how often this happens. Out of ideas? Make sure you’ve entered the number correctly. Especially if you’re messaging international numbers. Mistakes in formatting or forgetting to include the country code are common errors.
For instance, if you’re trying to message a number in Mexico, ensure it looks like this: +52 followed by the 10-digit local number.
- ❌ Incorrect: 528908949805
- ✅ Correct:+528908949805
Other common country codes include the UK (+44), the US (+1), and Canada (also +1).
12. Recipient has enabled Do Not Disturb (DND) settings
If the recipient has enabled Do Not Disturb (DND) settings, SMS delivery might be blocked. This is often the case for marketing or unsolicited messages since DND settings are designed to prevent unwanted interruptions.
However, if the recipient adjusts their DND preferences or temporarily disables the setting, the message delivery can be retried.
13. Roaming restrictions on the recipient’s device
Some mobile networks restrict SMS delivery to phones that are roaming internationally. This means that if the recipient’s device is outside their home country, messages may not be delivered, depending on the carrier’s roaming policies or the agreements between networks in different countries.
14. Time restrictions in specific countries
Certain countries impose regulations on the timing of marketing SMS messages. For example, in India, promotional SMS messages are only permitted between 9 AM and 9 PM. Messages sent outside these hours will be blocked.
Additionally, the Telephone Consumer Protection Act (TCPA) defines business hours for texting as between 8:00 AM and 9:00 PM in the recipient’s local time zone. Being aware of these restrictions helps you ensure successful delivery and avoid regulatory issues.
Get more reliable texting with OpenPhone
We hope this post sheds some light on the mysteries of SMS deliverability. We love helping professionals communicate seamlessly so if you have questions or need advice on your SMS-related issues, send us a note.
If you’re looking for a simple and reliable solution for texting, check out OpenPhone. We’re a modern business phone for small businesses and startups. It works right on top of your existing devices (via an app). We’ve got a free trial, so check it out for yourself and let us know what you think!
FAQs
An SMS message might not get delivered for a number of reasons, but some of the most common are:
– Recipient opted out of messages
– Recipient blocked your phone number
– Message contained illegal content
– Network problems with the recipient’s carrier
– Recipient’s phone is turned off or in airplane mode
Another less common reason is that SMS isn’t set as the default messaging app on your device. Go into your settings and make sure SMS is set as your default messenger, not RCS or another app.
Whether you’re an individual looking to send a group SMS or a professional needing to communicate with your team on the go, there are plenty of reasons why messages may not reach their intended recipient.
When you see that an SMS message is undelivered, it means the carrier couldn’t deliver the text to that phone number.
To ensure you don’t send out a text that never makes it to its recipient, make sure all your contacts have a valid number and they’re not using a device that doesn’t support texting, such as a landline phone. To proactively handle this, if they are opting into receiving texts from you, the field in your form can say “Cell phone number.”
If you’ve confirmed you have an active connection (through your mobile, data plan, or WiFi) and are still not able to send a message, your contact may have opted out of receiving messages from you. If you’re confident that’s not the issue, consider checking with your contact via email that you have the correct phone number on file.
Group messages on Android may not send if there’s an issue with your network connection, if the group message settings are disabled, or if one or more recipients are using a non-SMS platform (like iMessage). Make sure your mobile data is on and group messaging is enabled in your settings.
To troubleshoot a “message not delivered” error on your iPhone, check your network connection, ensure you have enough storage, and verify that the recipient’s number is correct. If the problem persists, try restarting your phone or resetting your network settings.
