diff --git a/common/src/main/java/me/lucko/luckperms/common/storage/DataConstraints.java b/common/src/main/java/me/lucko/luckperms/common/storage/DataConstraints.java
index 1c8b2fb05..e5ab999ee 100644
--- a/common/src/main/java/me/lucko/luckperms/common/storage/DataConstraints.java
+++ b/common/src/main/java/me/lucko/luckperms/common/storage/DataConstraints.java
@@ -38,7 +38,7 @@ public final class DataConstraints {
     public static final int MAX_GROUP_NAME_LENGTH = 36;
 
     public static final int MAX_PLAYER_USERNAME_LENGTH = 16;
-    public static final Pattern PLAYER_USERNAME_INVALID_CHAR_MATCHER = Pattern.compile("[^A-Za-z0-9_ ]");
+    public static final Pattern PLAYER_USERNAME_INVALID_CHAR_MATCHER = Pattern.compile("[^A-Za-z0-9_]");
 
     public static final int MAX_SERVER_LENGTH = 36;
     public static final int MAX_WORLD_LENGTH = 36;
diff --git a/nukkit/src/main/resources/config.yml b/nukkit/src/main/resources/config.yml
index 173e298fe..fdc784204 100644
--- a/nukkit/src/main/resources/config.yml
+++ b/nukkit/src/main/resources/config.yml
@@ -50,7 +50,7 @@ use-server-properties-name: false
 #
 # Note that due to the design of the storage implementation, usernames must still be
 # 16 characters or less.
-allow-invalid-usernames: false
+allow-invalid-usernames: true
 
 # If LuckPerms should produce extra logging output when it handles logins.
 # Useful if you're having issues with UUID forwarding or data not being loaded.