How to resolve this?

[MATR1X0]

[culturally]

You need to use country code with the number for example: The number is USA so you will use +1
so if the number looks like this (555) 555-5555
you will enter +15555555555. Also don’t forget that the api doesn’t work on certain countries. Here is a good example about E.164 format and how to use it.