If packet loss occurs while connecting a switch to a server, perform these steps: Verify that the cable is good by using a cable tester or replace it with a known good cable. Verify that the Network Interface Card (NIC) is compatible and working properly. Imagine ordering a desk that ships in five boxes. Boxes 1, 2, 4, and 5 arrive undamaged, but box 3—containing every last screw, bolt, and connector, of course—has gone missing in logistics-land. The first thing to do when troubleshooting it is to isolate where the loss is occurring. This guide will walk you through what causes this issue and. Packet loss occurs whenever a network packet doesn't reach its intended destination.