Not able to establish database connection -dberror(Connection.prepareStatement): 258 - insufficient privilege: Not authorized

I am new to SAP Hana cloud environment and was trying to learn sentiment analysis using Hana cloud platform. I am using the following code in my .xsjs script :

var body = "error";
var data = {
    result : 0
};


var id = Number($.request.parameters.get("id"));
var word = $.request.parameters.get("word");

if(word.length!==0) {
    try {
        var conn = $.db.getConnection();
        var query = 'call \"com.hana.cloud.platform.TwitterSenitmentAnalysis.DatabaseStore::update\"(?,?)';
        var cst = conn.prepareCall(query);
        cst.setString(1, word);
        cst.setInteger(2, id);
        var rs = cst.execute();
        conn.commit();

        rs = cst.getResultSet();

        while(rs.next()) {
            data.result = rs.getInteger(1);
        }

        body = JSON.stringify(data);

        rs.close();
        cst.close();
        conn.close();
    } catch (e) {

        body = e.stack + e.message;

        $.response.status = $.net.http.BAD_REQUEST;
        conn.close();
    }
}

I am able to use another xsjs service to connect to the database and perform select however when I try to perform update it gives me the following error :

Not able to establish database connection -dberror(Connection.prepareStatement): 258 - insufficient privilege: Not authorized

The schema name I am working with is called AMRIT and the user is called AMRIT as well. While trying to give object privileges to the AMRIT schema for the update I get the following error in the hana database cockpit:

8:07:22 PM (Security Editor) Changing 'AMRIT' user failed: 404 - Granting privilege 'UPDATE' on SCHEMA 'AMRIT' failed: insufficient privilege: Not authorized 

please assist on how to solve this?

Should I be giving any additional privilege to the system user?

Thanks, regards

Please give insert privilege on your schema to user _SYS_REPO.