Some chargers will not charge unless the battery has been discharge more than 80 pct.
This is to protect the battery.
You can try to take a long ride, and then see if it will start charging again.
@Losna Check the region of the user when talking about charging. Europe has some nice rules that the U.S. market does not have currently. What you describe does not fit for the cheap chargers and the limited BMS on batteries here. You are not wrong in theory. But in reality, you are off. Best to ask about the ebike in question before laying a general region specific rule for the rest. Welcome to the forum.