An L2VPN service has been created between two NSX environments within two separate software-defined data centers.
Both sites stretch overlay(VNI) segments.
DR downlink on either server or client side is configured as default gateway.
While the VM's on the Client side of the tunnel will likely be able to communicate with VM's on the Server side and vice versa.
VMs on one site can't ping the default gateway on the other site.
VMware NSX-T Datacenter
VMware NSX
Change the VDR MAC on either site so that both sites don’t use the same VDR MAC to fix this issue.
Refer official doc for the same: Changing VDR MAC Procedure
Note: While changing the MAC address of NSX Virtual Distributed Router, if a VM is attached to an NSX overlay segment, you might observe a short disruption in the data plane. Kindly plan the change accordingly.