It is no secret that in recent years, Epson has a tendency to bring trouble to the users under the guise of updates, particularly printer firmware updates. The next step in this direction was the replacement of some communication protocol specifications for a number of models, which makes waste reset and working with the printer via WIC when using Wi-Fi impossible. The main symptom that indicates the presence of this problem is the message "Query is rejected" when trying to perform any operation, including waste reset, as well as the firmware from the 2023 year or later (fifth letter is either N or O in the firmware name, for example CB10NB).
At the moment those models are affected:
L3250 (ET-2400 ET-2810)
L3260 (ET-2800 ET-2820)
L4260 (ET-2850)
WF-7820
WF-7830
WF-7840
The only solution is to either use USB connection or to downgrade the firmware to an earlier version. WIC provides a number of free 2022 firmware versions for the models from the list. To perform the downgrade you need to do the following:
1. Start WIC and unfold "Firmware Update" section (printer must be connected via USB).
2. From the list of firmwares select newest version available:
3. Press "Update" button to the right of the list and follow the instructions
Once firmware downgrade is succesfully finished, printer should work normally with the WIC.