Routing Stops for minutes and starts again with no intervention

I have two networks as part of my zerotier implementation. Network 1 and Network 2 and each network has a Raspberry PI 4 as its ZeroTier device. I require all traffic on Network 2 to route to Network 1 and utilize Network 1’s internet connection.

I configured this successfully on ZeroTier in October and it worked perfectly for many months. No issues at all and it has been always available.

Unfortunately over the last couple of months the routing stops for about 5-10 minutes every few hours. I do not have to touch anything and it resumes on its own. During the outage I have collected the following information.

RBP4-Network1 device can no longer ping RPB4-Network2 device INTERNAL IP ADDRESS and vice versa.

RBP4-Network1 device can no longer ping RPB4-Network2 device MANAGED IP (the ZeroTier address) and vice versa.

The ZeroTier GUI shows both devices as ONLINE.

RBP4-Network1 – sudo zerotier-cli info shows ONLINE
RBP4-Network2 – sudo zerotier-cli info shows ONLINE

When I join the ZeroTier network via my Mac and the current zerotier client I can maintain VNC connections to both RBP4-Network1 and RBP4-Network2.

It appears that routing between the RBP4-Network1 and RBP4-Network2 is failing during these periods HOWEVER when the Mac client joins natively it can see both RaspBerry PI’s via the Managed IP’s.

I hope this is clear. Anyone have any ideas?

Thank you