Invalid number of parameters ERROR: Invalid syntax. Default option is not allowed more than '2' time(s). Type "SETX /?" for usage. code example

Example 1: Invalid command 'SSLEngine', perhaps misspelled or defined by a module not included

sudo a2enmod ssl && service apache2 restart

Example 2: error: invalid use of template-name without an argument list

template<typename T>
LinkedList<T>::LinkedList()
{
   start = nullptr;
   current = nullptr;
}