Can't get session settings

I’m trying to get the Current Session settings from the online subsystem.
Get get it to work…

void UOnlineFunctionLibrary::GetSessionData(bool & IsValid)
{
	IOnlineSubsystem* Subsystem = IOnlineSubsystem::Get();
	if (Subsystem == nullptr)
	{
		IsValid = false;
		return;
	}
	IOnlineSessionPtr SessionInterface = Subsystem->GetSessionInterface();
	if (SessionInterface.IsValid())
	{
		FOnlineSessionSettings* CurrentSettings = SessionInterface->GetSessionSettings(GameSessionName);
		IsValid = true;
		return;
	}
	else
	{
		IsValid = false;
		return;
	}
}

When I try to compile this is what I get:

Error	C2027	use of undefined type 'IOnlineSession'

Error	C2039	'GetSessionSettings': is not a member of 'TSharedPtr<IOnlineSession,ESPMode::ThreadSafe>'	

How can I get the current (The session I’m connected to) Settings?

Thanks!

Forgot to add #include "Online.h"