When placing calls to any recipient using the Syniverse platform, you will need to ensure the phone number is formatted correctly.

For mobile recipients, you must add a "9" to the number after the country code, i.e. 5491123452345. Without this the calls to mobile numbers will fail with a SIP response of 404, 484 or 500 depending on the network. 

The "9" must not be inserted for calls to land line recipients, or the call will fail .