Created JWT and trying to use this.
App I am using is the only App in Production for sending SMS.
Using Rest Client with C#
restClient = new RestClient( "RC_CLIENT_ID", "RC_CLIENT_SECRET", "https://platform.ringcentral.com"); var jwt = @"REMOVED FOR SECURITY"; var tokenInfo = await restClient.Authorize(jwt);
Response: StatusCode: 400, ReasonPhrase: 'Bad Request', Version: 1.1, Content: System.Net.Http.HttpConnectionResponseContent, Headers: { Server: nginx Date: Fri, 11 Nov 2022 23:44:07 GMT Connection: keep-alive Vary: Origin Vary: Access-Control-Request-Method Vary: Access-Control-Request-Headers RCRequestId: bbd807d0-621a-11ed-884a-0050568d7d0d Pragma: no-cache Cache-Control: no-store AceRoutingKey: iad41-c01-ace01-f7db789cc-xzsz9_10.120.155.210 RoutingKey: SJC01P13 Content-Type: application/json Content-Length: 201 Content-Language: en } Content: { "error" : "unauthorized_client", "errors" : [ { "errorCode" : "OAU-251", "message" : "Unauthorized for this grant type" } ], "error_description" : "Unauthorized for this grant type" } Request: Method: POST, RequestUri: 'https://platform.ringcentral.com/restapi/oauth/token', Version: 1.1, Content: System.Net.Http.FormUrlEncodedContent, Headers: { X-User-Agent: Unknown/0.0.1 RingCentral.Net/5.18.0 Authorization: Basic REMOVED FOR SECURITY traceparent: 00-e7fec9cf088e5a8849d254c03b4eea14-a20c80fc5b02ce2f-00 Content-Type: application/x-www-form-urlencoded Content-Length: 770 } Content: grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-bearer&assertion=REMOVED-FOR-SECURITY