diff --git a/connector/src/main/java/org/geysermc/connector/utils/LoginEncryptionUtils.java b/connector/src/main/java/org/geysermc/connector/utils/LoginEncryptionUtils.java
index 3d4dd506..8a13d054 100644
--- a/connector/src/main/java/org/geysermc/connector/utils/LoginEncryptionUtils.java
+++ b/connector/src/main/java/org/geysermc/connector/utils/LoginEncryptionUtils.java
@@ -105,6 +105,10 @@ public class LoginEncryptionUtils {
 
             connector.getLogger().debug(String.format("Is player data valid? %s", validChain));
 
+            if (!validChain) {
+                session.disconnect(LanguageUtils.getLocaleStringLog("geyser.auth.login.form.notice.desc"));
+                return;
+            }
             JWSObject jwt = JWSObject.parse(certChainData.get(certChainData.size() - 1).asText());
             JsonNode payload = JSON_MAPPER.readTree(jwt.getPayload().toBytes());