Setup 802.3ad bonding under Debian Jessie with a HP 1920G switch

I've got a Debian Jessie server with two Intel i350 onboard 1Gbps NICs which I would like to bridge using 802.3ad protocol to my HP 1920G 48port managed switch.

Here is the kernel I'm running

~ % uname -a
Linux ltsp 4.9.0-0.bpo.3-amd64 #1 SMP Debian 4.9.30-2+deb9u5~bpo8+1 (2017-09-28) x86_64 GNU/Linux

I've setup the switch's LACP ports 3 & 4 for the 802.3ad, but when I try to connect my bonded network it complains that 'The ports configuration is improper for being attached'.

In my /etc/modules I have

# /etc/modules: kernel modules to load at boot time.
#
# This file contains the names of kernel modules that should be loaded
# at boot time, one per line. Lines beginning with "#" are ignored.

loop
vhost_net
bonding

I've installed ifenslave

sudo apt install ifenslave-2.6

Here is the /etc/network/interfaces file

auto lo
iface lo inet loopback

# bond0 is the bonding NIC and can be used like any other normal NIC.
# bond0 is configured using static network information.
auto bond0
iface bond0 inet static
    address 192.168.200.5
    gateway 192.168.200.1
    netmask 255.255.255.0
    dns-nameservers 8.8.8.8
    dns-search lan
    # Use IEEE 802.3ad LACP bonding protocol
    bond-mode 4
    bond-miimon 100
    bond-slaves none

#eth2 is manually configured, and slave to the “bond0” bonded NIC
allow_hotplug eth2
auto eth2
iface eth2 inet manual
      bond-master bond0
      bond-primary eth2

#eth3 ditto, thus creating a 2-link bond.
allow_hotplug eth3
auto eth3
iface eth3 inet manual
      bond-master bond0

Which gives the output

~ % cat /proc/net/bonding/bond0
Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)

Bonding Mode: IEEE 802.3ad Dynamic link aggregation
Transmit Hash Policy: layer2 (0)
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0

802.3ad info
LACP rate: slow
Min links: 0
Aggregator selection policy (ad_select): stable

Slave Interface: eth2
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 0
Permanent HW addr: 00:25:90:e6:e9:67
Slave queue ID: 0
Aggregator ID: 1
Actor Churn State: none
Partner Churn State: churned
Actor Churned Count: 0
Partner Churned Count: 1

Slave Interface: eth3
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 0
Permanent HW addr: 00:25:90:e6:e9:66
Slave queue ID: 0
Aggregator ID: 2
Actor Churn State: churned
Partner Churn State: churned
Actor Churned Count: 1
Partner Churned Count: 1

This doesn't work. I cannot ping this machine on 192.168.200.5. What am I missing here?

Update 23/08/2018

Tried setting bonding attributes in the modules file.

Edit /etc/modules

bonding mode=4 miimon=100 lacp_rate=1

Update 28/08/2018: more info from HP switch

display current-configuration in the HP command line gives me this output;

<HP 1920G Switch>display current-configuration
#
 version 5.20.99, Release 1106
#
 sysname HP 1920G Switch
#
 undo voice vlan mac-address 0003-6b00-0000
 undo voice vlan mac-address 00e0-7500-0000
 voice vlan mac-address 0004-1300-0000 mask ffff-ff00-0000 description SNOM phone
 voice vlan mac-address 0004-f200-0000 mask ffff-ff00-0000 description PolycomVVX phone
 undo voice vlan security enable
#
 domain default enable system
#
 ipv6
#
 telnet server enable
#
 lldp compliance cdp
#
 password-recovery enable
#
vlan 1
 description Data
#               
vlan 300
 description Voice_Polycom
#
domain system
 access-limit disable
 state active
 idle-cut disable
 self-service-url disable
#
user-group system
 group-attribute allow-guest
#
local-user admin
 password cipher <snip>
 authorization-attribute level 3
 service-type ssh telnet terminal
 service-type web
#
 stp mode rstp
 stp enable
#
interface Bridge-Aggregation1
 link-aggregation mode dynamic
#
interface NULL0
#
interface Vlan-interface1
 ip address dhcp-alloc
#
#
interface GigabitEthernet1/0/1
 description firewall
 port link-type trunk
 port trunk permit vlan 1 300
 port auto-power-down
 poe enable
 stp edged-port enable
#
interface GigabitEthernet1/0/2
 description LTSP
 port auto-power-down
 poe enable
 stp edged-port enable
#
interface GigabitEthernet1/0/3
 description Workstation_Phone_Prn_Scan
 port link-type trunk
 port trunk permit vlan 1
 port auto-power-down
 poe enable
 stp edged-port enable
 lldp compliance admin-status cdp txrx
 port link-aggregation group 1
#
interface GigabitEthernet1/0/4
 description Workstation_Phone_Prn_Scan
 port link-type trunk
 port trunk permit vlan 1
 port auto-power-down
 poe enable
 stp edged-port enable
 lldp compliance admin-status cdp txrx
 port link-aggregation group 1
#
interface GigabitEthernet1/0/5
 description Workstation_Phone_Prn_Scan
 port link-type trunk
 port trunk permit vlan 1
 voice vlan 300 enable
 port auto-power-down
 poe enable
 stp edged-port enable
 lldp compliance admin-status cdp txrx

GigabitEthernet1/0/3 & GigabitEthernet1/0/4 are the ports I'm trying to bond. You can see that they are part of the link-aggregation group.

Update: Looking at the logfile

To check the logfile I had to do this through the web backend 'device -> syslog' and after restarting the network on my test bonding machine I got these four lines;

Aug 28 10:59:06:287 2018    IFNET   Error   LINK_UPDOWN GigabitEthernet1/0/4 link status is UP.
Aug 28 10:58:56:005 2018    IFNET   Error   LINK_UPDOWN GigabitEthernet1/0/3 link status is UP.
Aug 28 10:58:43:066 2018    IFNET   Error   LINK_UPDOWN GigabitEthernet1/0/3 link status is DOWN.
Aug 28 10:58:33:338 2018    IFNET   Error   LINK_UPDOWN GigabitEthernet1/0/4 link status is DOWN.