API Error codes


The following error messages are generated by the Clickatell gateway during the validation phase by our REST, FTP, SMTP and SOAP APIs before a message is accepted. These error messages are sent back to your application as API responses. There will be no message charge if these errors are generated when sending a message. Data regarding messages that don’t pass initial validation will not be included in your Developers’ Central reports.


Error Code


Detailed Description



Authentication failed

Authentication details are incorrect.



IP lockdown violation

You have locked down the API instance to a specific IP address but attempted to send from an IP address different to the one you have set.

You can edit the setting to include your new server’s IP address or remove the IP lockdown completely within Developers’ Central’s API settings.


Data malformed

The JSON/XML data submitted is invalid.

Check that the syntax of your request has been formulated correctly and resubmit.


Invalid or missing parameters

One or more parameters are missing or invalid.



Invalid user data header

The format of the user data header is incorrect.

Ensure valid UDH data is being passed to the API.


Invalid destination address

The destination address you are attempting to send to is invalid.

Check that the number of the handset that you are attempting to send a message to is valid. The number should be in an international format, without a ‘ 00’ prefix or leading ‘+’ symbol OR begin with a ‘0’ if the default country prefix is enabled on your API.


Invalid source address

The specified sender address is incorrect.

The address that the message is sent ‘from’ has been specified incorrectly. If you are using a Sender ID as your source address, ensure that it has been registered within your online Developers’ Central account.


Invalid or missing API ID

The API ID is either incorrect or has not been included in the API call.

Include the correct API product ID in your query. You can check the ID that is associated with your API by logging into your Developers’ Central account.


Missing message ID

This may refer to either a client message ID or API message ID – for example, when using the ‘stop message’ command.



Maximum message parts exceeded

The text component of the message is greater than the permitted 160 characters (70 Unicode characters). View the concatenation page for help in resolving this issue.

Set concat equal to 1,2,3-N to overcome this by splitting the content across multiple messages. View concatenation information.


Cannot route message

This implies that the gateway is not currently routing messages to this network prefix. Please email support@clickatell.com with the mobile number in question.



Invalid unicode data

The format of the Unicode data entered is incorrect.

Ensure that the Unicode format is correct and resubmit your query.


clientMessageId contains space(s)

Your specified client message ID contains a space. Space characters in client message IDs are not currently supported.

The delivery time must be entered in minutes up to a maximum of 7 days.


Destination mobile number blocked

This number is not allowed to receive messages from us and has been put on our blocked list.



Destination mobile opted out

The user has opted out and is no longer subscribed to your service.



Invalid Sender ID

The sender ID is not valid or has not been approved.

A sender ID needs to be registered and approved before it can be successfully used in message sending.


Number delisted

This number has been delisted and cannot receive our messages.



Maximum MT limit exceeded until <UNIX TIMESTAMP>

This error is returned when an account has exceeded the maximum number of MT messages that can be sent daily or monthly. You can send messages again on the date indicated by the UNIX TIMESTAMP.



HTTP method is not supported on this resource

An unsupported HTTP method has been performed on the resource. Example: HTTP POST on the Coverage resource.

The response MUST include a Content-Type header that contains a valid method for the requested resource.


Resource does not exist

You are attempting to access a REST API resource that does not exist.



Invalid or no version header specified

The expected header that specifies version was either not found or is invalid.

Before continuing, make sure that the correct version is included in the submitted header. The header to use is X-Version: 1


Invalid accept header specified

The optional header that specifies acceptable content does not contain an allowed value.



Invalid or no content-type specified

The expected header that specifies content-type content was either not found or did not contain an allowed value.

Before continuing, make sure that an allowed value is included in the submitted content-type header. The allowable content-type header values are ‘application/json’ or application/xml’.


Destination address is on DNC list – Do not contact receiver

DNC lookup for the destination address result shows that the receiver should not be contacted.

Use the “bypass_dnc_check” (this name varies for APIs) request parameter to bypass the DNC check.


No credit left

Insufficient credits.

Log in to your Developers’ Central account and purchase additional credits.


Internal error – please retry

An error occurred on our platforms.

Please retry submitting the message. This should be exceptionally rare.


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