Canon WFT-E8A Instruction Manual page 131

65: Wireless LAN connection lost
Are any obstacles blocking the line of sight between the

transmitter and the antenna of the access point?
Move the antenna of the access point to a position clearly visible

from the point of view of the transmitter (p.136).
The wireless LAN connection was lost, for some reason, and

the connection cannot be restored.
The following are possible reasons: excessive access to the

access point from other terminals, a microwave oven or similar
appliance in use nearby (interfering with IEEE 802.11n/g/b (2.4
GHz band)), or influence of rain or high humidity (p.136).
66: Incorrect wireless LAN encryption key
Are the transmitter and the access point set to use the same

encryption key for authentication?
 The setting is case-sensitive, so check upper- and lower-case
characters. Make sure that the correct encryption key for
authentication is entered on the transmitter and the access point
(p.32).
Note that if the authentication method is [Open system], an Error
41 ("Cannot connect to FTP server") is displayed.
Responding to Error Messages
131