Nexon Wrote:

We are aware of an issue with Norton AntiVirus that causes a false positive detection between Norton SONAR, and NGS and Black Cipher. This is preventing some players from being able to play MapleStory.

We are working to resolve the issue soon. For now, there is a workaround that you can use in order to play. Please follow the steps below:

1. Go into Norton.
   
2. Click on "Settings" at the top.
   
3. Click on "AntiVirus".
   
4. Under “SONAR Advanced Mode”, the "Remove Risks Automatically" option is default set to "High-Certainty Only".
   
5. Click on this to change it to the “Ask Me” option.
   
6. Click "Apply".