My fitbit Versa is not charging

It could be either, it’s hard to say for certain. Was it working fine previously? If so, the battery seems to be fine unless it was left out for ages, depleting the battery to the point where you have to charge it for a while for anything to happen. It could also just be the charger as if it is not going on charge or recognising that it should be charging then that may be your issue. I would say the charger is more likely and one to start with but if still nothing, then definitely battery.

I have a magnetic charger connection on my fitbit sense. A few days ago I found my charger lead connecter clinging to my metal bin. It wouldn't work after that so it occurred to me after checking the pins one had retracted into the plastic which had slightly melted. The bin must of shorted the pins. When I removed the connecter from the bin, the pin must of receded into the melted plastic created by the short. I am only guessing this is the reason, I may be way off the mark.