Canon EOS REBEL T6 W Instruction Manual page 94

Responding to Error Messages
23: Device with same IP address exists on selected
network
What to check on the camera
Is another device on the camera network using the same IP

address as the camera?
Change the camera's IP address to avoid using the same address

as another device on the network. Otherwise, change the IP
address of the device that has a duplicate address.
If the camera's IP address is set to [Manual setting] in network

environments using a DHCP server, change the setting to [Auto
setting] (p.51, 67, 70, 74).
Responding to Error Messages 21 - 23
Also check the following points when responding to errors numbered 21 -
23.
Are the camera and the access point set to use the same encryption
key for authentication?
 This error occurs if the encryption keys do not match when the
authentication method for encryption is set to [Open system]. 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 camera (p.50, 73).
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