If the laser used to work, and now doesn’t, and nothing else has changed, check to make sure you can ping the laser - literally type the command PING followed by the IP address of your laser in a command prompt and press enter.
If that fails, there’s some issue with the connection itself - possibly physical like a bad cable, or the short extension cable between the laser case and the controller has failed, or it could be that your networking router decided to assign the same IP you use for the laser to something else on your network.
Reviewing the post Rick linked above about connecting via Ethernet is good just for a refresher.