Solutions
Turn off the devices you want to connect to the network. Wait for about 10 seconds, and then turn on the devices in the following order; wireless router, computer or smart device, and then printer. Move the printer and computer or smart device closer to the wireless router to help with radio wave communication, and then try to make network settings again.
Solutions
After moving the computer or the smart device closer to the wireless router, turn off the wireless router, and then turn it back on.
Solutions
Make the connection settings again so that they match the new wireless router.
Solutions
Most wireless routers have a privacy separator feature that blocks communication between connected devices. If you cannot communicate between the printer and the computer or smart device even if they are connected to the same network, disable the privacy separator on the wireless router. See the manual provided with the wireless router for details.
Solutions
If the IP address assigned to the printer is 169.254.XXX.XXX, and the subnet mask is 255.255.0.0, the IP address may not be assigned correctly.
Print the network connection report, and then check the IP address and the subnet mask assigned to the printer.
Reset the network settings for the printer.
Solutions
Try accessing any website from your smart device to make sure that your smart device's network settings are correct. If you cannot access any website, there is a problem on the smart device.
Check the network connection of the computer. See the documentation provided with the smart device for details.