If you're having problems with message delivery, more often than not it is due to an issue with the supplier/carrier or invalid credentials. It is also important to note that different countries have different rules and regulations in place that can also affect message delivery.
If a message cannot be found in your outgoing report, you will need to look at the method by which you sent your SMS in order to troubleshoot this problem. See What to do if a message is not in my outgoing report? for more information on troubleshooting this issue.
Please note, delivery receipts aren't always supported in certain countries.
Below are the main factors that may be causing SMS delivery issues:
Account Credit
Ensure that your account has a sufficient credit balance to send your messages. If not, please top up your account and try sending the messages again. Messages sent while there is no credit in your account will not automatically send once your account has been topped up. You must send the messages again, or reach out to the SMSGlobal support team for assistance.
Missing API Request
Ensure that your API request is correct and confirm that you're not missing a parameter in your request.
Invalid Numbers
If your delivery status report is showing 'Invalid Number', then the destination number may not have been recognised by SMSGlobal. Ensure that the number is in its correct International Format with the correct country prefix and the correct number of digits.
If the phone number you have entered is a landline, SMS messages will not be supported. In this case, the messages will be rejected and will not be delivered to the recipient. If you suspect that this may be the issue please request an MNP Lookup to identify if the number is invalid.
Further details in: What does it mean when a number is invalid?
Recipients Handset
There may be an issue reaching the recipient's handset if the mobile is not within mobile range or switched off. Message delivery will be reattempted and the message status should update after 48-72 hours.
The recipients may have also changed mobile numbers or carriers, this may result in a message failing to send.
Invalid Sender ID
Messages showing a status of 'Undelivered' may be a result of an invalid Sender ID being used. Each country has different restrictions and regulations in place meaning that not all Sender ID’s are supported. If your Sender ID is not supported in a certain country you're sending to, your message may not deliver. Please check that the Sender ID you’re using is supported in the country you’re trying to send SMS messages to.
For more information on Sender ID's please see What is a Sender ID or Common Sender ID issues
Message Content
Please check the content of your message; be aware that not all message content is supported by governing bodies in certain countries and could affect messages sending.
For example, the delivery may be affected if:
There's a URL in the body of your message.
There's content related to gambling/betting/adult content in your message.
There's a Unicode in your message.
Your message is split into multiple parts (sometimes, very long multipart messages, e.g. longer than 4 or 5 messages, can cause problems for certain destinations).
If you need any further assistance to troubleshoot delivery problems, please contact SMSGlobal support.
In the ticket, please include as much detail as possible to help our support team investigate your case, particularly:
Your SMSGlobal username
Mobile Number(s) of the recipients not sending
Time/Date of send attempt
The country you're sending to and the Sender ID that you're using to send
Sending method (API, Email to SMS, MXT portal)