Hello, and thank you for choosing JA for your support needs. Happy to assist you with this issue.
The message means the Waste Toner Box is nearly full and will need to be replaced or emptied out. You need only Buy a new Waste Toner Box from you local Retailer in your area. Staples, Best Buy, Office Maxx, Office Depot and many others.
Please let me know if you need any more assistance, Sir or Madam.