ExecuteScalar can not find stored procedure

I use the library "Dapper" to connect with MS Sql.

When I call stored procedure, it show error message

can not find stored procedure.

But stored procedure it already exist in Database. How can I resolve this problem? thanks.

public static string WrtoLogDb(string id, string id1)
{
    using (var conn = new SqlConnection(connStrTest))
    {
        try
        {
            conn.Open();
            var strf33_schD = conn.ExecuteScalar<int>("exec DelClsCourTimeTest", new { id,  id1 }, commandType: CommandType.StoredProcedure);
            return strf33_schD.tostring();
        }
        catch (Exception EX)
        {
            return EX.ToString();
        }
    }          
}