The printer and the access point (wireless LAN router) has been connected successfully but the printer cannot be connected to the computer through an access point (wireless LAN router). Try the following solutions in order.

Check the privacy separator function on the access point (wireless LAN router)
This is a common problem for mobile wireless LAN routers. A privacy separator function that cuts off communication between devices is enabled in the access point (wireless LAN router). This is a security feature to cut off communication between devices through the router. When enabled, because the printer and computer communication is cut off, they cannot be connected. Disable the privacy separator function on the access point, and then set the network again. See your access point manual for details on the setting method. Depending on the manufacturer, the privacy separator function may have a different name.

Check the SSIDs for the printer and the computer
Some access points can have multiple SSIDs. Some are able to separate the SSIDs into the corresponding wireless standard (IEEE802.11a and IEEE802.11g). Even with the same access point (wireless LAN router), the printer and the computer use different SSIDs, and they may not be able to communicate. Match the SSID of the computer with that of the printer. You can check the computer’s SSID on the Wi-Fi connection menu. The printer’s SSID is on the printed network diagnostic report. Once the SSIDs match, set the network again.