Some more information would be helpful in trying to find the cause for the issue you're running into:

• What is the exact error message you are seeing
• Are there any errors recorded in your vsFTPD error logs in /var/log from your login attempts
• Are you trying to log in as the root user? Another user account?
• Was this configuration previously working and what if any changes were made since that time.

The more detail you can provide, the more likely we'll be able to help you find the root cause and resolve it.