Can someone please help with adding an extra IP ??? I tried everything :(

I have a server on Hetzner and I have successfully added in the past a /29 subnet and an extra single IP.
Now however I am trying to add another extra single IP and whatever I have tried it just doesn’t work.
I usually don’t write into forums without trying all I can so please any help is much appreciated!

This is the contents of my current /etc/network/intefaces file (I have changed slightly the IPs for security reasons).


+++++++++++++++++++
# network interface settings
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 5.9.66.48
netmask 255.255.255.224
broadcast 5.9.66.64
gateway 5.9.65.33

auto vmbr0
iface vmbr0 inet static
address 78.47.219.71
netmask 255.255.255.248
bridge_ports none
bridge_stp off
bridge_fd 0

auto vmbr1
iface vmbr1 inet static
address 192.168.0.1
netmask 255.255.255.0
bridge_ports none
bridge_stp off
bridge_fd 0
post-up echo 1 > /proc/sys/net/ipv4/ip_forward
post-up iptables -t nat -A POSTROUTING -s '192.168.0.0/24' -o eth0 -j MASQUERADE
post-down iptables -t nat -D POSTROUTING -s '192.168.0.0/24' -o eth0 -j MASQUERADE


# bridge for VMs with public IPs (DMZ)
auto vmbr2
iface vmbr2 inet static
address 5.9.66.48
netmask 255.255.255.224
bridge_ports none
bridge_stp off
bridge_fd 0
up ip route add 5.9.66.57/32 dev vmbr2
#
#
#
auto vmbr3

iface vmbr3 inet static
address 5.9.66.48
netmask 255.255.255.248

bridge_ports none
bridge_stp off
bridge_fd 0
up ip route add 5.9.104.60/32 dev vmbr3

+++++++++++++++++++



5.9.66.48 is the main server IP
78.47.219.71 is one of /29 IPs assigned to a bridge to provide connectivity to the remaining IP (Works)
5.9.66.57 is the 1^st single extra IP (Works)
5.9.66.48 is the 2^nd extra IP which I am having problems getting it to work




The IP settings inside the KVM are

IP: 5.9.66.48
Netmask: 255.255.255.248
Gateway: 5.9.66.48
KVM is Bridged to vmbr3



Note: The IP details provided by Hetzner for the 2^nd extra IP are:

IP: 5.9.104.60
Netmask: 255.255.255.248
Gateway: 5.9.104.57
Broadcast: 5.9.66.64


I have tried with and without a MAC address given by Hetzner, however no luck.

What am I doing wrong here?!?!

:(