@senopatib first try this. Turn your phone off. Then connect the charger. See if it does now charge. if you are sure that there is no moisture in the USB port and if you already cleaned it with isopropyl alcohol etc. it is time to replace the port. Of course, on this phone the port is soldered to the logic board which would require some board level soldering. If this is above your level of comfort, consider getting in touch with somebody who does board level repair. Check [https://www.youtube.com/watch?v=0ZjDjt6YSW4] as well before working on it. [https://www.youtube.com/watch?v=pcT-Z1YVsOA|This video] shows you how to replace the port. It's not as easy as the video makes it seem. It'll take some experience to do the soldering.