Can you tell me what browser you're using?
It sounds like your browser ran out of storage, so it's unable to save new games. WarLight tries to automatically delete unnecessary data when it runs out of space (such as cached maps, etc.), but it doesn't work sometimes and I'm trying to figure out why (it seems to be dependent on browser).
This problem is made worse by having "enable hard disk storage" enabled, since that causes maps to cache which takes up some of the space.
You can go to https://www.warlight.net/Test/LocalStorage
to see how much space you're using. Most browsers cap this at 5mb. You can clear everything in your local storage here, or also clean up space by deleting games at https://www.warlight.net/SinglePlayer/SavedGames
If you can't get it working, please contact me at https://www.warlight.net/ReportBug
Edited 11/11/2016 20:20:14