回复：下载了该说明书，把Lansetting 中Tenda router 从192.168.2.1改成 192.168.0.2,

Try this:

Cisco router LAN side DHCP setting:

See if the Starting IP Address is 192.168.0.2.  If yes, change it to, say, 192.168.0.10.

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You probably have a PC or other device occupying 192.168.0.2