wmoetaua, there are multiple reasons that you should check out. Firs start with the charger, make sure it works. If it does, replace the cable. If it still does not charge, replace the battery. Now it gts complicated. Still not charging, check the charging port connector. For that you will have to disassemble your phone. Check [https://www.youtube.com/watch?v=q4e-5xkhvHA|this video] on how to fix the port. Lastly, it could be possible that this is caused by your Power Management IC, which would require a boardlevel repair.