Proxmox node freezes

Machine that freezes:
roland@documentation:~$ ip addr show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 32:30:31:63:63:31 brd ff:ff:ff:ff:ff:ff
    inet 192.168.121.44/24 brd 192.168.121.255 scope global eth0
       valid_lft forever preferred_lft forever

Machine that doesn't freeze:
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 16:71:aa:ad:6b:d7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.121.56/24 brd 192.168.121.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::1471:aaff:fead:6bd7/64 scope link
       valid_lft forever preferred_lft forever

From the proxmox node:

# arp -a
in.gtst.xyz (192.168.121.1) at 00:16:36:76:13:94 [ether] on vmbr0
backupvm (192.168.121.34) at 92:b6:c1:78:1c:f6 [ether] on vmbr0
s2.gtst.xyz (192.168.121.32) at 00:16:36:76:0f:3d [ether] on vmbr0
wiki.imb.co (192.168.121.44) at 32:30:31:63:63:31 [ether] on vmbr0
h1.gtst.xyz (192.168.121.30) at d8:fe:e3:a7:21:a9 [ether] on vmbr0
www.gtst.xyz (192.168.121.56) at 16:71:aa:ad:6b:d7 [ether] on vmbr0
web1 (192.168.121.130) at 5a:28:d7:84:8b:47 [ether] on vmbr0