On Mac, network drives are mapped automatically when using Finder. When not in use, their mapped network drives are disconnected by the system. This can happen while Pinker is running, and Pinker cannot re-map this drives automatically.
The workaround is to open disconnected drives in Finder. This re-maps them and makes them again available to Pinker or follow the instructions in https://www.tekrevue.com/tip/automatically-connect-network-drive/