Getting 403 Not allowed to send promotional SMS(s).

[prasad4491]

Not allowed to send promotional SMS(s).

I just created account with trail period. But I am unable to send sms. Please let me know the reason

curl --location --request POST 'https://<api_key>:<api_token>@api.exotel.in/v1/Accounts/<Account_sid>/Sms/send.json'
--header 'Accept: application/json'
--header 'Content-Type: application/x-www-form-urlencoded'
--data-urlencode 'From=XXXXXXXXX'
--data-urlencode 'To=XXXXXXXXX'
--data-urlencode 'Body=Hello World1'