setup was fine but now my computer and phone just won't find the epson et-2850 on wifi anymore.

Diagnosis

The Epson EcoTank ET-2850 frequently suffers from a "Network State Mismatch." This occurs when the printer maintains a cached IP address that no longer aligns with the DHCP lease assigned by your router. If your router rebooted or updated its firmware, it may have assigned a new internal IP to the printer, but your computer and phone are still attempting to send data packets to the old, expired address. This results in the devices reporting the printer as "Offline" or "Not Found" even if the printer's screen shows a signal icon. Another common culprit is the 2.4GHz vs 5GHz band steering. The ET-2850 only supports 2.4GHz wireless bands. If your router uses a single SSID for both bands (Smart Connect), the printer can get "kicked" off the network when the router attempts to force it onto the 5GHz band, which the printer's hardware cannot physically sustain. To confirm this, print a Network Status Sheet from the printer menu; if the IP address is 169.254.x.x, the printer has failed to obtain a valid IP from your router and is effectively invisible to your network.

How to Fix It

To resolve the connection drop and re-establish a handshake between your devices and the ET-2850, follow this precise sequence:

1. Power cycle the hardware: Turn off the printer, unplug your router from the wall for 30 seconds, and restart your computer/phone. Plug the router back in and wait 3 minutes for the network to fully stabilize.
2. Reset the Printer Network: On the ET-2850 control panel, press the Home button. Navigate to Settings > General Settings > Network Settings > Restore Default Settings. Confirm the reset. This clears the corrupted IP cache.
3. Re-run the Setup Wizard: Go back to Settings > Network Settings > Wi-Fi Setup. Select Wi-Fi Setup Wizard. Select your network SSID from the list and enter your password. Ensure you are entering the password for the 2.4GHz band.
4. Verify Connectivity: Once the screen says "Setup Complete," go to Network Settings > Print Status Sheet. Check the printed page to ensure the "IP Address" is a valid local address (typically starting with 192.168.x.x).
5. Refresh Device Connection: On your computer, open the Epson printer preferences. If the printer is still offline, remove the device from "Printers & Scanners" in your OS settings and click "Add Device" to let the computer discover the new IP address.

If That Didn't Work

• Assign a Static IP Address: Access your router's admin panel (usually 192.168.1.1) via a web browser. Find the DHCP client list, locate the ET-2850, and select "Address Reservation" or "Static IP." This prevents the router from changing the printer's address in the future, which is the primary cause of the "Printer Offline" error.
• Disable 5GHz Band Steering: If your router supports it, create a separate SSID specifically for 2.4GHz devices (e.g., "MyHome_2G"). Connect the ET-2850 exclusively to this band. This stops the router from attempting to "upgrade" the printer to a frequency it cannot support.
• Update Firmware via USB: If the wireless connection is too unstable to update, connect the printer to your PC via a USB-B cable. Run the Epson Software Updater tool on your PC to check for firmware updates. Newer firmware versions for the ET-2850 include stability patches for WPA3 security protocols.
• Check Firewall/Antivirus: Some third-party security suites (like Norton or McAfee) identify the Epson discovery port as a threat after a network change. Temporarily disable your firewall to see if the printer immediately appears. If it does, add the Epson printer's IP address to your "Trusted Zone" or "Whitelist."

Heads Up

• Avoid placing the printer directly next to the router; a distance of 3-5 feet is ideal to prevent signal "swamping" or electromagnetic interference.
• If you change your Wi-Fi password, you must perform the "Restore Default Settings" step mentioned above before the printer will accept the new credentials.
• Avoid using "Wi-Fi Direct" for permanent setups. Wi-Fi Direct creates a separate network that disconnects your phone/PC from the internet while printing; always use "Infrastructure" mode for home networks.
• Periodically check the ink levels via the screen rather than the app; if the printer is offline, the app will show outdated ink levels, which can lead to air bubbles in the print head if you attempt to print without enough ink.