Go to your router configuration page, and make sure no-one is connected to your network. That may be the issue. Otherwise I'm not sure, keep scanning your PC everyday just incase you are actually infected by malware that is currently not detected by your antivirus.
Whenever I try to connect via FTP in filezilla, I get this:
Response: 331 User kodi OK. Password required
Command: PASS **************
Response: 530 Login authentication failed
Error: Critical error: Could not connect to server