Error: "cannot access the private member declared in the class" boost :: signals2 :: scoped_connection "?

class Whatever
{
public:
    virtual ~Whatever();

protected:
    Whatever();
    virtual void SomeMethod();
    void OnEventOccurred(int x);

    std::vector<boost::signals2::scoped_connection> boostSignalConnections_;
}

//.cpp

Whatever::SomeMethod()
{
    ...
    boostSignalConnections_.push_back(
        anObject->AddEventOccurredObserver(
            std::bind(&Whatever::OnEventOccurred,
                      this, std::placeholders::_1)));
    ...
}

(Note AddEventOccurredObserverjust delegates boost::signals2::connect()and returns boost::signals2::connection)

I get the following error. It's hard to interpret template errors, but it seems like an error occurs when declaring a memberstd::vector<boost::signals2::scoped_connection> boostSignalConnections_;

...\vc\include\xmemory(202): error C2248:  
    'boost::signals2::scoped_connection::scoped_connection' :
    cannot access private member declared in class 'boost::signals2::scoped_connection'
...\boost_1_47\boost\signals2\connection.hpp(234) : see declaration of
'boost::signals2::scoped_connection::scoped_connection'
...\boost_1_47\boost\signals2\connection.hpp(210) :
    see declaration of 'boost::signals2::scoped_connection'
...\vc\include\xmemory(201) : while compiling class template member function
'void std::allocator<_Ty>::construct(boost::signals2::scoped_connection *,_Ty &&)'
with
[
    _Ty=boost::signals2::scoped_connection
]

I searched, and I think this could be due to the fact that scoped_connection is not being copied? I'm not sure. The reason I use scoped_connection is related to this SO question: Handle the connection / disconnection of many signals / slots with boost :: signals2

Update

FYI, scoped_connection connection, : std::vector<boost::signals2::connection> boostSignalConnections_;. scoped_connection , , , connection . .