Hello,
If the router and switch are on different subnets or VLANs, devices on one subnet/VLAN cannot see devices on another subnet/VLAN if routing is not set up correctly. First make sure all devices (router, switch, and computer) are on the same subnet. You can try pinging the computer connected to the switch from the computer connected to the router. If the ping fails, there is a network connectivity problem between the router and the switch.
Best Regards
Zunhui