if you have any other phone which is C Type and supports 20W or more try that charger on it.
if not then i would really recommend you just go to Samsung and get it checked as i had the same problem but mine was a bit different in my case the charger just suddenly stops charging any phone.
i got it replaced.
Since your device requires physical inspection, kindly visit the nearby Samsung service center.
After physically examine your device, service center personnel will provide you the further resolution.
For address details of Samsung Service Centers follow the link mentioned below-
Team Samsung Members