Define a Role that Grants Privileges in sap hana trial account?

Hello Experts,

Earlier we were able to define roles by creadting .hdbrole and pasting the below code in that file

role<user>.helloworld.sample::model_access {

          sqlobject<user>.helloworld.sample.data::mytable: SELECT,INSERT;

}

Now after the changes in the trial account cloud not able to perform grant privileges.

Please  help me ASAP.

Thanks

Kapil