Will not charge, the charger is working

First clean the charging port with a firm bristle brush (toothbrush). Then inspect port and make sure the tongue isn't bent. Try to charge. If it still doesn't charge. Use the disassemble guide. Only go far enough to use a volt meter to see where the problem lies. 95% of the time it is bent prongs (tongue) of the charging port; created from improper mounting of the charging cord. Sometimes it is simply dirty, and unfortunately sometimes the port will come completely separated from the board. This is from improperly inserting the cord and then trying to force it in, instead of reinserting the charging cord properly. Last but not least, from forcing the wrong charging cord into the charging port. Good luck