Do you have the IP (subnets) of the remote networks you are trying to reach in the 'Private Subnets' section of your Non Meraki VPN Peers. I believe you also need to make sure the subnet suffix matches on each side. For troubleshooting support can also do a capture in the VPN tunnel so you can verify if your traffic is actually going over the tunnel to their side or truly dropping at the MX.
Adam R MS | CISSP, CISM, VCP, MCITP, CCNP, ITILv3, CMNO If this was helpful click the Kudo button below If my reply solved your issue, please mark it as a solution.
Turned out to be routing on the other side, due to reasons of how the customer does this we basically were not getting responses from the target machine. But they have checked/amended the routing and now we get replies.
Turns out the Meraki VPN setup was fine all along 😉