Plivo - Document
Auth Id From Plivo Auth Token From Plivo
https://www.plivo.com/docs/voice/getting-started/basic/making-outbound-calls/
Abstract The actual issue is consider two mobile phones like Cell A and Cell B. If a call triggered from cell A to Cell B means Cell B will display cell A number. Here Cell B (Network) is not verifying or authenticate like these call is originally triggered from cell A. What cell B actually doing means it simply display that incoming number in Mobile panel.
Solution: 1.API Network needs to validate from number(Like it should not allow other numbers as from number). 2.Telecom Network need to authenticate that call from number.