When your M2Guard license expires, players will not experience any issues logging into the game. They will still be able to access the game, but the anti-cheat protection provided by M2Guard will stop working until the license is renewed. This means that any cheats or bots that were previously detected and blocked by M2Guard will no longer be prevented, and players may be at risk of encountering cheating behavior.
However, it's important to note that server owners can still manage their server and player base during this time, and can choose to renew their license at any point to restore anti-cheat protection.