Why am I unable to send text messages to international numbers?

Hi Grace, you can check if you have insufficient balance to send messages to an international number.
You can use this link to check the international rate depending on the country and the network you are sending the SMS to: https://www.mtnonline.com/personal/international-sms-rates/
Since you can send local SMS, it means that your message center number should be correct.
If the issue persist, you need to contact MTN support for assistant.
You can contact MTN support via any of these channels:
1. MyMTN App
2. Facebook: @MTNLoaded
3. Instagram: @MTNNG
4. Live Chat: http://bit.ly/2OC5bHz
5. Email: customercareng@mtn.com
6 .WhatsApp: 09033000001

Why can’t I send texts to international numbers?