I have set up an app that calls a web hook on an incoming call and managed to do soon initial testing fine by calling the main number. I have moved the app to the clients account and have it in the sandbox, but when I call the main number (sandbox) I get a voice response "The number you have dialled is temporality unavailable" and that is all I get. The configuration looks to be the same as my developer account, and I am at a bit of a loss at working out what is happening.
Any help would be appreciated .