Normally you should migrate from Password flow to JWT flow, which is kind of equivalent and suitable for Server/No UI app platform type.
If you really want to change the authentication to OAuth 2.0 code flow, the best option is to register a new app with code flow with a specified the Redirect URI and you will need to implement extra code to handle the authorization.
Ok I updated, the settings of my console to use JWT, I then using Postman (for testing) used this URL: https://platform.ringcentral.com/restapi/oauth/token
POST Request
Headers:
Content-Type = application/x-www-form-urlencoded
Authorization = Basic (base64encode"clientid:clientsecret")
Params:
assertion = my JWT token I generated under credentials
grant_type = urn:ietf:params:oauth:grant-type:jwt-bearer
( Note I also tried : grant_type = urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-bearer )
However this is the error I get which is the exact same error I got when using OAuth 2.0:
{ "error": "invalid_request", "errors": [ { "errorCode": "OAU-250", "message": "Unsupported grant type" } ], "error_description": "Unsupported grant type"}
I am using cURL, because I am using the FileMaker platform, thanks in advance for any advice.
