NIC Link up but no traffic flowing

[akc360]

Hello Proxmox Community,

I have been using Proxmox for about 2 years now and it is great. I have just been given a Mellanox ConnectX 4 Lx Dual port 25Gb NIC and installed it to my main server. Proxmox recognises the card and also recognises the link as 10Gb active which is correct. Unfortunately I can't seem to get any traffic to flow on this NIC. I have tried the NIC the same server same PCIe slot with Truenas Scale and can confirm the NIC works fine with that OS. Below are the server hardware and software info and also the anonimised (with x's) outputs of "ip a" and "/etc/network/interfaces/".

Xeon Silver 4214
AsrockRack EPC621D8A
Samsung RDIMM 64GB
Mellanox ConnectX 4 Lx Dual port 25Gb NIC latest firmware available
Proxmox 8.3-1

auto lo
iface lo inet loopback

iface enp23s0 inet manual

iface enxfee07c3753c6 inet manual

iface ens20f0np0 inet manual

iface ens20f1np1 inet manual

auto vmbr0
iface vmbr0 inet static
        address 1xxxxx/24
        gateway 1xxxxx
        bridge-ports enp23s0
        bridge-stp off
        bridge-fd 0

auto vmbr1
iface vmbr1 inet manual
        bridge-ports ens20f0np0
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids x-x
#10Gb Bridge

auto vmbr1.x
iface vmbr1.x inet static
        address 1xxxxx/24
#Admin VLANx

source /etc/network/interfaces.d/*

root@prox1-mgmt:~# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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 noprefixroute
       valid_lft forever preferred_lft forever
2: enp23s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr0 state UP group default qlen 1000
    link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff
4: ens20f0np0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master vmbr1 state UP group default qlen 1000
    link/ether xx:xx:xx:xx:xx:x brd ff:ff:ff:ff:ff:ff
    altname enp101s0f0np0
5: ens20f1np1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff
    altname enp101s0f1np1
6: vmbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether xx:xx:xx:xx:xx:fc brd ff:ff:ff:ff:ff:ff
    inet 1xxxx/24 scope global vmbr0
       valid_lft forever preferred_lft forever
    inet6 xxxx::xxxx:xxxx:xxxx:xx/64 scope link
       valid_lft forever preferred_lft forever
7: vmbr1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff
    inet6 xxxx::xxxx:xxxx:xxxx:xxxx/64 scope link
       valid_lft forever preferred_lft forever
8: vmbr1.x@vmbr1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/etherxx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff
    inet 1xxxx/24 scope global vmbr1.x
       valid_lft forever preferred_lft forever
    inet6 xxxx::xxxx:xxxx:xxxx:xxxx/64 scope link
       valid_lft forever preferred_lft forever
root@prox1-mgmt:~#

Any help greatly appreciated! unfortunately and am at the end of my skill level with this

Many Thanks

Alex