That is pinging to the gateway IP on the same switch, the same IP is pingable externally without any problems which makes me think the switch is fine.

64 bytes from 55.55.55.55: icmp_seq=4 ttl=255 time=1.07 ms
64 bytes from 55.55.55.55: icmp_seq=1 ttl=255 time=3536 ms
64 bytes from 55.55.55.55: icmp_seq=2 ttl=255 time=2536 ms
64 bytes from 55.55.55.55: icmp_seq=3 ttl=255 time=1536 ms
64 bytes from 55.55.55.55: icmp_seq=8 ttl=255 time=1.20 ms
64 bytes from 55.55.55.55: icmp_seq=5 ttl=255 time=3636 ms
64 bytes from 55.55.55.55: icmp_seq=6 ttl=255 time=2636 ms
64 bytes from 55.55.55.55: icmp_seq=7 ttl=255 time=1636 ms
64 bytes from 55.55.55.55: icmp_seq=12 ttl=255 time=0.597 ms
64 bytes from 55.55.55.55: icmp_seq=9 ttl=255 time=3734 ms
64 bytes from 55.55.55.55: icmp_seq=10 ttl=255 time=2735 ms
64 bytes from 55.55.55.55: icmp_seq=11 ttl=255 time=1735 ms

This server hadnt' been accessed in days and at first responded normally and then started doing the above.  I did a network restart on the server and then it's been fine ever since.

Is it possible the NIC was put to sleep and then didn't come back properly, kind of like laptop WiFi after sleep?