New Apple Watch series 3 not charging

I have a new (as in it was never used before) Apple Watch series 3 with original charging cable that was working fine at first when it was given to me about 3 weeks ago but now it won’t charge. I did the troubleshooting, eg., I hard restarted it and that worked once but now that doesn’t work either, I made sure there were no protective stickers on anything and that the charger disc and back of the watch are clean but still nothing. It shouldn’t be glitching this soon. Back story, my friend gave it to me because it had been a gift to her husband a few years ago but he never once took it out of the box or used it, so it’s essentially brand new and used for the very first time about 3 weeks ago. Please help! Thanks.