Why this happens? Why SMS messages are not delivered sometimes?

Carriers have filters in place to block spam messages and protect their customers from unwanted messages. If your SMS message is flagged as spam, it may not be delivered. Some common reasons why messages are filtered as spam include:

  • Using all caps or excessive punctuation in the message body
  • Sending too many messages in a short period of time
  • Sending messages with a suspicious or spammy content
  • Including a large number of links or attachments
  • Links in message have poor reputation
  • Poor Reputation of Phone Number
  • Sending messages from a number that has been reported as spam
  • Message content filtered due to repetitive message (Use personalize message: Hi ((First_Name)) or use split test step to send multiple types of messages)

It's important to follow best practices for sending SMS messages to avoid having them filtered as spam. This includes using proper grammar and avoiding the use of all caps or excessive punctuation, sending messages with relevant and non-spammy subject lines, and avoiding sending large numbers of messages in a short period of time.

What you can do to avoid this?

1. White List your phone number:

In an effort to protect end users against unwanted calls, carriers and consumer application providers have been increasingly blocking or labeling calls that they feel fit typical robocalling campaign characteristics, such as high call volumes and short or unanswered calls. When their own analytics indicate potentially unwanted traffic, carriers may respond by blocking calls or inserting “Spam Likely”, “Telemarketer”, “Fraud Likely”, or other similar labels to display on the handset.

This kind of call analysis is difficult because while fraudulent robocalls often do show some of these characteristics, so can many legitimate use cases, including school closing notifications, weather alerts, and patient reminders, that recipients want and have opted-in to receive. Still, when viewed en-masse at the network level, they can look like illegal robocalling.

Use below link to follow procedure how to white list your phone number: https://support.flowtrack.co/How-to-White-List-your-Phone-Number-1d429979928e498e8e377982b57ded63

2. Send Personalized Messages

Sending personalized SMS messages is a good way to avoid having your messages filtered as spam. Here are a few tips for sending personalized SMS messages:

  1. Use the recipient's name in the message: Personalizing the message with the recipient's name can help to increase engagement and reduce the likelihood of the message being marked as spam.
  2. Write in a conversational tone: Write the message as if you were having a conversation with the recipient. This will help to make the message feel more personal and less like a generic marketing message.
  3. Provide value: Make sure that the recipient will receive some sort of value from the message, whether it be information, a special offer, or something else.
  4. Avoid spammy words and phrases: Words and phrases that are commonly used in spam messages, such as "free" or "limited time offer", can trigger spam filters. Avoid using these words in your messages.

By following these tips, you can increase the likelihood that your SMS messages will be delivered and not filtered as spam.

3. Build a Solid Sending Reputation

A solid sending reputation is essential for ensuring that your SMS messages are delivered and not filtered as spam. Here are a few ways to build a solid sending reputation for SMS:

  1. Get permission: Only send SMS messages to people who have opted-in to receive messages from you. This can help to reduce the likelihood of your messages being marked as spam.
  2. Personalize your messages: Personalizing your messages with the recipient's name, using a conversational tone, and providing value can help to increase engagement and reduce the likelihood of your messages being marked as spam.
  3. Monitor your delivery rates: Regularly monitor your delivery rates to ensure that your messages are being delivered and to identify any potential issues that may be affecting your sending reputation.
  4. Avoid sending too many messages: Sending too many messages in a short period of time can trigger spam filters and harm your sending reputation. Make sure to pace your messaging and avoid sending too many messages at once.

By following these tips, you can build a solid sending reputation for SMS and increase the likelihood that your messages will be delivered to your intended recipients.

4. Contact Receiving Carrier

If you are experiencing issues with SMS delivery and have tried all of the above steps to resolve the issue, you may need to contact the recipient's carrier for assistance. Here is how you can contact the recipient's carrier:

  1. Identify the carrier: You can usually identify the carrier by the recipient's phone number, or by looking it up online.
  2. Find the carrier's customer support number: You can typically find the carrier's customer support number by searching for it online or by visiting the carrier's website.
  3. Explain the issue: When you call the carrier's customer support, explain the issue you are experiencing with SMS delivery and provide as much detail as possible, including the recipient's phone number and the messages that were not delivered.
  4. Follow up: If the issue is not resolved immediately, make sure to follow up with the carrier to ensure that it is being addressed.

By contacting the recipient's carrier, you may be able to get more information about the issue and find a solution to the problem.