Thanks Gaurav. I tried to create the token but am getting the below error . I am trying to do POST request using Rest client and seeing the below error in POSTMAN.

Error in error.log -- >
20.03.2019 12:38:38.876 *ERROR* [qtp1411610424-69] org.apache.felix.http.jetty Exception while processing request to /oauth/token (java.lang.IllegalStateException: Committed)
java.lang.IllegalStateException: Committed
at org.eclipse.jetty.server.HttpChannel.resetBuffer(HttpChannel.java:894) [org.apache.felix.http.jetty:4.0.6]
at org.eclipse.jetty.server.HttpOutput.resetBuffer(HttpOutput.java:959) [org.apache.felix.http.jetty:4.0.6]
at org.eclipse.jetty.server.Response.resetBuffer(Response.java:1312) [org.apache.felix.http.jetty:4.0.6]
at javax.servlet.ServletResponseWrapper.resetBuffer(ServletResponseWrapper.java:195) [org.apache.felix.http.servlet-api:1.1.2]
at org.apache.felix.http.base.internal.dispatch.ServletResponseWrapper.sendError(ServletResponseWrapper.java:67) [org.apache.felix.http.jetty:4.0.6]
at org.apache.felix.http.base.internal.dispatch.ServletResponseWrapper.sendError(ServletResponseWrapper.java:61) [org.apache.felix.http.jetty:4.0.6]
at com.adobe.granite.oauth.server.impl.OAuth2TokenEndpointServlet.doPost(OAuth2TokenEndpointServlet.java:183) [com.adobe.granite.oauth.server:1.1.26]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:644) [org.apache.felix.http.servlet-api:1.1.2]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725) [org.apache.felix.http.servlet-api:1.1.2]