usb port

A single USB port on my recently purchased iMac (purchased 09/2019) is not working. When I plug in a device, it is not being recognized by the iMac. The other 3 USB ports are working. I have shut down and unplugged the computer twice. One time I pressed the power button for 5 seconds while the computer was unplugged as per recommendations from articles on the internet. Same single USB port still not working. Any suggestions how to fix?