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Until and unless the response code with error message is given here, it's difficult to say about the reason of the 403 error. It may be of many reasons like invalid client, invalid grant_type etc.

You need to provide the error code in the response here

Until and unless the response code with error message is given here, it's difficult to say about the reason of the 403 error. It may be of many reasons like invalid client, invalid grant_type etc.

You need to provide the error code in the response here

To get a list of valid SMS numbers, list your phone numbers by calling the 'account/~/extension/~/phone-number' endpoint and then filter by phone numbers with the 'SmsSender' feature.

Here is some documentation on this:

http://ringcentral-api-docs.readthedocs.io/en/latest/messages_sms-and-pager/#listing-valid-sms-sendi...

Hi,

403 is HTTP Code. Also you should be provided with response body having additional details like errorCode and appropriate message, e.g.:

HTTP 403

{    "errorCode" : "FeatureNotAvailable",    "message" : "The requested feature is not available",    "errors" : [ {      "errorCode" : "MSG-242",      "message" : "The requested feature is not available"    } ]   }

In RC logs I can see 3 different error codes for your account: 
# MSG-242 //Sending SMS is not available from the number specified.
# MSG-304 //Phone number doesn't belong to extension
# MSG-240 //Specified recipient [${toPhoneNumber}] isn't an US phone number

Please advise if you still have any questions.

Thanks,

thank you for your reply,
here is my function it practically send a message through the java rest api the uri are ok and the only important thing here are the phone numbers message.sendSms("myaccount-phone", "to-phone", "this is me if you get this acknowledge");the to-phone is a mobile phonethe response doesn't specify any error message besides 403another thing this is a sandbox accountthank you

Hi Sami,

Could you please provide request and response? The might be a different reasons of 403 Forbidden response, e.g. SMS feature is not available, ineligible Phone Number, insufficient User/Application permissions, etc. 

Thanks!