Bought an iPad Mini 2nd hand and my daughter ran the battery down completely. Plugged it into the charger and I got the battery with the red bars at the bottom of the battery but wasn’t seeing the lightning bolt saying it’s being charged. I tried different chargers, different lightning cables but nothing would work. Had it plugged into a charger all night and it still wouldn’t charge. Tried the alternating the home and sleep buttons solution that I’ve seen on many message boards and even tried cleaning the lightning port on the iPad.
My iPad Mini has a SIM slot and I remember reading that someone fixed this problem on their iPhone by removing the SIM card and then plugging it in. So that is what I did. Removed the SIM and within a minute the Apple logo popped up and is now charging.