Unable to send SMS messages from MobileIron console

I recently installed a MobileIron core for a new customer.

During the initial configuration and testing phase I was successfully able to send enrolment invitations via SMS from the MobileIron console to both Vodafone and Spark devices.

A week or so later when the customer did some testing of their own they found that messages, although sent successfully would only arrive on Vodafone devices but would not arrive on Spark devices.

MobileIron support confirmed that the messages were being correctly sent by the MobileIron core to their provider Clickatell, who in turn advised that they had successfully sent the SMS messages to both Spark and Vodafone devices.

A support call to Spark Digital NZ, revealed that Clickatell does not have a direct SMS agreement with them, so they could not help troubleshoot the issue further.

A support call to Clickatell revealed that they use a number of different upstream providers to route SMS messages and use an automated “least cost routing” system to route the messages.

In this case the least cost route had been blacklisted for potentially sending spam, so Clickatell manually updated their SMS routing system to resolve the issue.