Cannot Send or Receive SMS

User level: Admin

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Symptoms

You may notice one or more of the following:

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When sending SMS

• The message fails immediately
• The SMS appears as “Sent” but the recipient does not receive it
• Messages deliver to some numbers but not others
• A long message becomes multiple separate messages
• The sender number changes unexpectedly

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When receiving SMS

• No inbound messages appear in the CloudTalk app
• You receive some messages but not others
• Verification codes (OTP / 2FA) never arrive
• Older SMS conversations disappear from the app
• An inbound reply arrives as a short word or reaction phrase such as “love”, “happy”, “y”, or Loved "…" / Liked "…", instead of the message you expected

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How SMS Works in CloudTalk

CloudTalk supports P2P (peer-to-peer) conversational SMS. However, SMS functionality varies by:

• country
• number type
• destination network
• telecommunication regulations

Before troubleshooting, please note:

• Not all CloudTalk numbers support SMS
• Not all countries support international SMS
• Many services do not send OTP/2FA codes to VoIP numbers
• Some carriers rewrite the sender number to ensure delivery
• Long or Unicode messages are split into fragments
• Trial accounts can send up to 10 SMS fragments only

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Root Causes

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⚠️ Your number is not SMS-enabled

Not every CloudTalk number supports SMS. Some numbers are voice-only because of the rules and capabilities in the country where they were purchased. For example:

• Some local numbers in certain countries do not allow SMS through VoIP providers.
• Many toll-free numbers support voice only and do not support SMS at all.
• Some mobile number ranges can only send outbound SMS but cannot receive them.
• In some countries, SMS can only be delivered domestically and not internationally.
• Older numbers on your account may have been purchased before SMS coverage was available for that region.

This is expected behavior and depends on local telecom regulations, not on your CloudTalk plan.

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⚠️ New US number: A2P 10DLC registration required

If you have a new US number, SMS will be disabled until you complete A2P 10DLC brand and campaign registration. This is a US carrier requirement for all business messaging (application-to-person), not a CloudTalk limitation. Until registration is complete, you can’t send SMS from that number, even if your account and plan support SMS. When you open a chat on the number, the app shows a notice above the message box and blocks sending:

• Admins see why SMS is blocked and a Register in Dashboard button.
• Agents see “SMS is not available for this number. Contact your account admin.”

To complete registration and enable SMS on your US number, follow the steps in Registering Standard USA Numbers for Messaging (A2P 10DLC).

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⚠️ “Invalid number”: the contact’s number is missing the country code

If a message shows Not delivered: Invalid number, check that the contact’s number is saved in full international format, starting with + and the country code (for example, +18434796102, not 18434796102). Update the contact’s number and send the message again.

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⚠️ Destination country limitations

Each country has its own rules about what kind of SMS can be delivered. Some limitations you may come across include:

• International SMS not supported
• Only certain number types allowed (for example, mobile only)
• No long messages or no multi-fragment messages
• Local networks rewriting the sender number

If SMS work to one country but not another, this is often the reason.

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⚠️ CloudTalk trial limits

Free trials include up to 10 SMS fragments for testing. Once the limit is reached, SMS will stop working until the account is upgraded. The limit cannot be extended.

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⚠️ Message content is prohibited

Some types of content are blocked automatically by destination carriers, especially in USA / Canada. These restrictions apply even when sending SMS manually from CloudTalk. Examples of restricted or blocked content include:

• high-risk financial content
• affiliate or lead-generation marketing
• gambling
• adult content
• debt-related content
• risky or misleading marketing phrases

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⚠️ OTP / 2FA messages cannot be received

CloudTalk numbers are VoIP-based, and many banks, apps, and online services do not send one-time passwords (OTP) or two-factor authentication (2FA) codes to VoIP numbers. Even if regular SMS works, verification codes sent by SMS may never arrive. If you need to complete verification, many services allow you to request an authentication phone call instead of an SMS code. These calls usually work with CloudTalk numbers. If possible, we still recommend using a personal mobile number or another authentication method for critical account access. Learn more about OTP / 2FA limitations here.

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⚠️ The message is too long or uses special characters

Messages with emojis, accents, or non-standard characters use a different character set, which reduces the number of characters allowed in a single SMS.

• Standard characters: up to 160 per SMS
• Unicode characters: up to 70 per SMS

If your message exceeds these limits, it will be split into multiple fragments. Some destinations do not support combining fragments, which may cause the full message not to be delivered.

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⚠️ The sender of the inbound message uses an unsupported format

CloudTalk cannot receive SMS from:

• alphanumeric senders (names instead of numbers)
• short codes
• certain automated systems
• apps that mask their sender ID

This is why one-time passwords, login verification codes, and two-factor authentication messages often do not arrive. Only SMS sent from a regular long-code phone number can be received.

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⚠️ SMS are not visible in the CloudTalk app

CloudTalk Phone shows only a limited number of recent SMS conversations to keep the app fast and responsive. The app displays up to 100 recent conversations in total:

• 50 most recent inbound conversations
• 50 most recent outbound conversations

Once these limits are reached, older conversations automatically roll out of view. Individual conversations also have limits on how many messages can be displayed. These older SMS are not deleted, they simply no longer appear in the app. If you need access to historical messages that are no longer visible, CloudTalk Support can export them on request.

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⚠️ Local carriers may change the sender number

When sending SMS internationally, some networks replace your sender number with a different one to ensure delivery. This is common and not a CloudTalk issue. However, it can cause confusion if the recipient tries to reply to the modified number and the reply never reaches you.

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⚠️ Inbound replies that show up as a reaction word or phrase

If an inbound reply arrives as a single word like “love”, “happy”, or “y”, or as a short phrase like Loved "your message" or Liked "your message", this is usually an emoji reaction from the sender, not a truncated or broken message. When someone reacts to a text on their phone (for example, a heart or thumbs-up “tapback” on an iPhone) rather than typing a reply, their device may send that reaction as a plain SMS. Depending on the sender’s phone and carrier, it can arrive as a descriptive phrase (Loved "…") or as a single word (“love”, “y”). This conversion happens on the sender’s side before the message reaches CloudTalk, so the exact wording varies and isn’t something CloudTalk controls. CloudTalk receives and displays exactly what the carrier delivers. This is not a CloudTalk bug, and CloudTalk cannot detect or reverse the conversion. What you can do:

• If you just need a normal reply, ask the sender to type their message instead of reacting to it.
• If you believe a full message was sent but arrived incomplete (not just a reaction), ask the sender to screenshot what they typed. If that screenshot shows a full message that doesn’t match what appeared in CloudTalk, contact Support with the sender’s number, your CloudTalk number, the date and time, and the screenshot, so we can escalate to the carrier.

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Step-by-Step Troubleshooting

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Check the message status

Start with the message itself. A red mark next to a chat in the Messages list means its last message failed, so open that chat first. Every message you send shows a status icon next to it. On desktop, hover over the icon to see the status:

• Delivered: the message reached the recipient’s phone. If they say they didn’t get it, the issue is on their device.
• Sent: the message is on its way. If it stays on Sent, keep reading below.
• Not delivered: the recipient’s carrier rejected it. The most common causes are destination country limits, blocked content, or an unregistered US number (see Root Causes above).
• Failed: the message never left CloudTalk. Tap it to resend.

See Text Messaging for more on message statuses.

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Check that your number supports SMS

CloudTalk Phone will show you immediately if a number does not support SMS. You can check this directly in the app:

1. Open CloudTalk Phone (Desktop or Web).
2. Look at the bottom navigation bar, where the icons for Calls, Contacts, Dialpad and Messages are located.
   
3. If SMS is not supported for the number you are currently using, the Messages icon will be greyed out and cannot be clicked.
4. When you hover your cursor over the Messages icon, a small tooltip appears explaining that SMS is not supported for this number.

This is the quickest way to confirm that your number is voice-only or does not include SMS capability. If the Messages icon is active (in color), the number is SMS-capable and you can start sending and receiving text messages.

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Can I switch a voice-only number to SMS-enabled?

In most cases, capabilities cannot be changed because they depend on the telecom infrastructure in the country where the number originates. However, you can replace your number with another number that fully supports SMS if the country and number type allow it.

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How to get an SMS-capable number

1. Go to Numbers > Get a number.
2. Select the same country as your current number.
3. Choose a number type that supports SMS (for example, mobile instead of local, if available).
4. If you do not see any SMS-capable options, submit an assisted request and mention that you specifically need SMS support.

Your Account Manager or Support can help you choose a number type that supports SMS in your region. Send SMS to:

• your own mobile
• a number in the same country as your CloudTalk number
• a number in a different country

If some messages arrive and others do not, the issue is likely country-specific or related to the destination’s mobile network. If the message is long or includes emojis, accented characters, or formatting, try simplifying it. This reduces the number of fragments and helps with delivery in countries that do not support multi-fragment messages. Some types of message content are blocked by destination carriers, especially in countries with strict filtering rules. If you are sending regulated or sensitive content, check whether it falls into a restricted category, including:

• financial services or loan offers
• affiliate or lead-generation marketing
• cannabis / CBD
• gambling or betting
• 3rd-party debt collection
• sensitive categories such as sex-related content, hate-related content, alcohol, firearms, or tobacco

If a message includes restricted content, it may be filtered or blocked without any delivery error. If you are not receiving inbound SMS:

• Ask someone to send a message from a standard mobile number
• Do not test with short codes or app verification systems (these usually will not work)

If long-code messages arrive but app verification messages do not, the behavior is expected. If messages were previously visible but no longer appear, it may simply mean that the app has reached its limit for how many SMS conversations and messages it can display. To keep CloudTalk Phone fast and stable, only a certain number of recent conversations and messages are shown, and older ones are automatically hidden from view. These older SMS are not deleted. They just no longer appear in the app. If you need access to older SMS, CloudTalk Support can export them for you.

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When to Contact Support

Contact CloudTalk Support if:

• Your number is SMS-enabled but cannot send or receive any SMS
• SMS fail to all destinations
• Inbound SMS worked previously and suddenly stopped
• Messages stay on Sent or show Not delivered, and none of the causes above apply
• You need older SMS exported from the database
• You suspect country-specific blocking or carrier restrictions

Include:

• Your number
• Destination number(s)
• SMS message example
• Timestamp of the failed attempt
• Screenshot of the message in CloudTalk
• Whether you are on trial or a paid plan

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Need help or have a question? Just reach out through our Support portal — we’re here for you.