Most people moved on to CnCNet. XWIS is, unfortunately, pretty baron. You can still access the XWIS server if your serial is still active, otherwise, EA Play/Origin version of the game, then install the WOL Internet Components into the game folder.
https://xwis.net/dl/WOLAPI-0.0.0.exe
Use the XWIS Client to set the IP to the XWIS server: https://xwis.net/dl/XWISC.exe