If you've found that recently your messages have started failing to send via the REST or SOAP API, it could have something to do with your operating system's security compliance.
On August 1, 2022 we stopped supporting TLS 1.0 and 1.1 – meaning that anyone using the API to send messages would need to ensure their operating system is compliant with TLS 1.2 or higher. You can read more about this here.
To check if your system is compliant with TLS 1.2 or higher, click here.
If you're sure that this is not the cause of the problem, contact our support team at email@example.com.