Network settings that were changed such as IP address, subnet mask, disabled dynamic IP address (DHCP) can be returned to the settings when it was purchased.
When you have changed the wireless LAN settings of the main unit, and it can no longer connect to a network, try configuring the settings again after initializing (/resetting) the network settings. Connect Tablet/PC
Caution
Reset network settings of printer
on the back of the device for 13 seconds.
located on the side of the device; hold down the *RST button until you hear three mechanical sounds. 
Note
When the network settings are initialized, the following items are restored to the setting when it was first purchased.