VLAN subnets overlaps Z4 to forti firewall VPN

[M.Sultan]

Hi engineers,

Trying to build site to site vpn from Z4 Meraki to forti firewall but meraki dashboard pop below messages, What would be the reason and the solution ?

The VLAN subnet 172.21.16.8/29 overlaps with a remote VPN subnet on the non-meraki peer Forti-W1 (172.16.0.0/12). IP traffic will be routed to the smallest subnet that Contains the IP address.

The subnet on the non-meraki peer Forti-W1 (172.16.0.0/12) overlaps with the subnets on networks London1 (172.21.16.0/29) and Z4 (172.21.16.16/29). IP traffic will be routed to the smallest subnet that Contains the IP address.

[Kasun Bandara]

@M.Sultan hi, seems like your remote subnet in Fortigate using sub network inside your meraki main network. you need to make sure IP addresses are not overlapping. and are you need 172.16.0.0/12 in your network ? the whole subnet?