Hi Toni,
if it looks like it’s charging, it would be battery issue - your battery is out of date and needs a replacement.
But for sure, first, check if your cable is OK and also if the power adapter is working properly, try different type of cable and adapter, then check, if the connector in the tablet is fine and is not damaged, clean it from the dust and try to charge. If it’s still not working, try to recover your tablet to the factory settings. If it’s still same, it’s time to replace your battery.