That’s because you need to verify that you’re following the game’s X account before you can even paste a code in. To do so, follow the Slap Battles X account, then type your @ into the codes ...

Go to Twitter (X) and follow @Slap_BattlesRBX. Open Slap Battles from the official Roblox page. Click the bird icon to open the Codes box Enter your Twitter username and click Verify @username.