If you have error 'No engines are working' you need to go to ADMIN in NPrinting tab and get ENGINE working in first place.
Your engine could stop workin due to many reasons:
- DNS name of server was changed
- Maybe ports are blocked
- Check Engine service (whether it is running)
- Maybe account for Engine service is locked
Start investigation from beginning by checking services, then accounts, then ports and then contacting network admins and making sure that server name is still the same