Thank you for your answer.
Before answer, each week we must reboot NAS because its performance is slowed.
I could view these error after reboot NAS (3 hours), but it was always slow after shutdown...
I will update firmware to 7.0up12 (actually 7.0up11).
Is-it possible in your interface to see bandwidth and W/R to each user ?
In the Console screen in CTRL ALT N then select the NIC and look in the Info section you will see speed and other information for the RX and TX values as well. For the users you will need to see from there systems there speed.