Ah very important detail, IP plan changed.
Means all the clients are still configured for checking in with the old IP adres.
The quickest way is to reinstall everything (server/client). Im guessing you dont have a large network since you run the server on your own computer.
You could also search the forum here for changing the IP address of the server and you will get some hits, i dont use the product you have so i cant help you any further.