Oof… if it happened suddenly with time left before decay, you likely violated a rule or multiple rules. Large walls extending too far from base? Decorative land claim (braziers or useless, but pretty structures to keep people from encroaching)? Killed a spawn of a boss, npc, or rare material? Blocked off a certain area of the game or built so much that it crashed people trying to get by? Any of these can be a factor for base removal. Also, you’ll likely be banned and anyone that was in your clan come the server reset tonight. Typically it’s a two week ban from all official servers.