Canon i-SENSYS MF729Cx Important Safety Instructions And Installation Manual page 612

The toner cartridge used may not be a genuine Canon product.
Only genuine Canon toner cartridges should be used as replacement toner cartridges.
Consumables
Use Remote UI to set the information necessary for authentication.
The IEEE 802.1X settings are incorrect.
Check whether [Login Name] is set correctly.
Check whether the [Use TLS], [Use TTLS], or [Use PEAP] check box is selected.
If using TLS, check whether a key pair is registered.
If using TTLS or PEAP, check whether a user name and password are set correctly.
Configuring IEEE 802.1X Authentication
Yellow cartridge has reached the end of its lifetime.
The toner cartridge has reached the end of its lifetime.
Replacement of the toner cartridge is recommended.
How to Replace Toner Cartridges