I am using uart communication between esp32 to x-bee cellular 3G modem.I am using using 3.3 v cell. The issue is arise during when cell totally discharged (2.4-2.5v). Recharging is start and after 2.6 voltage, controller will start working . but this time tx(red ), rx(green ) led shows continue HIGH. after 3.3 voltage uart still not working. After clicking the reset button issue remain same.