For channels that use WSHttpContextBinding with the NotAllowed value set, the context cannot be retrieved on the client using IContextManager because a new channel that establishes a session is created each time GetProperty<T> is called to enforce NotAllowed semantics on a channel. This means that even though the context is properly propagated back to the client in this case, it cannot be retrieved using IContextManager. You can still retrieve it using ContextMessageProperty as shown in the following code.
using (new OperationContextScope((IContextChannel)channel))
if (ContextMessageProperty.TryGet(OperationContext.Current.IncomingMessageProperties, out context))
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)