A320 neo stock aircraft at gate from cold and dark on Xbox. Received the above message from ATC, can you help?

This is because some airfields and some gates / stands don’t have a push back tug available. In these circumstances ATC will say that no tug is available. You might find with some 3rd party airports there is a pushback tug model, but it has not be set up by the developer to respond to ATC.