Hello @JJW. Please confirm that the "Public IP address/hostname" is the peer address of the far-end MX. Also, local IDs and Remote IDs may not be necessary depending on whether or not your MXs are behind another device and are being NAT'ed.
Hello @JJW, one of the other things to be aware of is that you need to make sure that one (or more) subnets are enabled for VPN traffic. As @DarrenOC already noted, verification that the peer is configured with matching security parameters is necessary. I have included a link to our documentation should you require additional help. At the bottom of the page, there is also a link to our troubleshooting guide.
Hello @JJW. Please confirm that the "Public IP address/hostname" is the peer address of the far-end MX. Also, local IDs and Remote IDs may not be necessary depending on whether or not your MXs are behind another device and are being NAT'ed.