Sorry about the inconvenience.
Please take into account and try to rule out the router’s distance as a source of error.
Also, please do not edit the aforementioned wpa_suplicant, it is not the protocol in use by Max2Play.
If you want to access it manually these are the paths:
/etc/network/interfaces -> wlan0 /opt/max2play/wpa_supplicant.conf
Please also make sure that you properly reboot the device after entering your WiFi credentials and remove the ethernet cable during reboot to make sure it prioritizes WiFi and does not autoset the old ethernet connection.