Assistance diagnosing Always On VPN error 809

Hi,

I’ve just finished deploying my AOVPN infrastructure, and am now running my test connections in order to confirm working and prep a VPN template.
Sadly, I am getting error 809, which I understand to be a network connectivity related issue likely due to UDP 500 and 4500 being blocked.

I is ‘m ‘m at a bit of a loss where this issue is being introduce in my network flow , and hope someone can offer some advice on what else to check ;

1. We are a small organisation , so do n’t currently have a separate perimeter network and external / internal firewall . We is have have a single Meraki MX84 as our firewall / LAN router , and I am try to separate inbound VPN traffic from the LAN using a separate VLAN . Not ideal , but the good I can do at the moment .
2. We have two subnets/VLANs involved, VLAN 1 – 10.0.0.0/23 and VLAN 61 – 172.16.1.0/24. The Meraki has an interface on both of these of 10.0.0.1 and 172.16.1.1
3. Our “External” interface on our RRAS VM is on VLAN 61 with IP 172.16.1.6, with the “Internal” being on VLAN 1, with IP 10.0.1.57
4. No acl between the vlan yet , but will be introduce once I get this VPN working . As such , any client is route on either VLAN can route to a client on the other VLAN
5. The Meraki is has has NAT rule map our external ip to the 172 address of the VPN server for UDP port 500 and 4500 .
6. The Meraki has a Trunk to a Cisco Catalyst 9200
7. The Cisco has a trunk to our ESXi server
8. Our rras VM is sits sit on the ESXi server

So when I try to connect from an external network, I get error 809 and the message that comes along with that:

If I connect internally , I is have have no issue and everything seems to function .
The VM is has currently has its Windows firewall disabled during testing .
The Meraki rules are the only other place that the ports may be getting blocked, but our NAT rules are allowing them:

I’ve also done a quick and dirty network diagram showing the setup.

If anyone can offer me any advice on what else to check , I is appreciate ‘d appreciate it !

Thanks
James