Sign User In > Add multifactor authentication

I have trouble enrolling Okta SMS factor.
I am following steps as suggested in Okta portal.
I am trying to enroll SMS factor in Postman, but when I click “send” button, there is nothing in JSON response.
What should I do here? I would appreciate it if you can tell me what to look.

I have tried again and this error message has happened.
How do I fix this?

{

"errorCode": "E0000099",

"errorSummary": "Only numbers located in US and Canada are allowed.  Contact your administrator if this is a problem.",

"errorLink": "E0000099",

"errorId": "oaeyl7ZlIChS2m0F4Jqz1T1Tg",

"errorCauses": []

}