Canon EOS 5D Mark IV Instruction Manual page 161

65: Wireless LAN connection lost
Are any obstacles blocking the line of sight between the

camera 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 camera (p.166).
The wireless 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 device, a microwave oven or similar
appliance in use nearby (interfering with IEEE 802.11b/g/n (2.4
GHz band)), or influence of rain or high humidity (p.166).
66: Incorrect wireless LAN encryption key
Are the camera 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 set on the camera (p.71).
67: Incorrect wireless LAN encryption method
Are the camera and the access point set to use the same

encryption method?
The camera supports the following encryption methods: WEP,

TKIP, and AES (p.60).
If filtering by MAC address is active, is the MAC address of the

camera used registered at the access point?
Register the MAC address of the camera used at the access point.

The MAC address can be checked on the [View info] screen
(p.144).
Responding to Error Messages
161