The open method must be the first method called after creating a QAManager.
If a database connection error is detected, you can re-open a QAManager by calling the close function followed by the open
function. When re-opening a QAManager, you do not need to re-create it, reset the properties, or reset the message listeners.
The properties of the QAManager cannot be changed after the first open, and subsequent open calls must supply the same acknowledgement