SuiteCRM Access token API returns 500 Internal error


In Postman Tool, we have checked the Access token generation API using client_credentials details. The Suite CRM version we have used is V7.11.8. While calling the API, it shows a 500 internal server error. If you can help to solve this issue, it will be highly appreciated. I really appreciate any help you can provide.

The API we are using is: rooturl/Api/access_token