I just recently experience with one of my Z1 that it drops site-to-site VPN frequently and every time this happen i have to power cycle the device to bring back the VPN. the WAN connection is 100% up all the time. what could possibly the cause of this?
my topology is hub -spoke, MX100 is the hub connecting site-to-site VPN with 6 spokes.
When you look at the appliance status page and hover over the green/red areas for the historical connectivity messages, is it just the general "no connectivity" or something else? And when clicking on the "Uplink" tab, looking at the latency & loss graphs over different time frames, there is no apparent pattern or timing to the loss of VPN connectivity? Beyond that, if there's nothing obvious when searching the event logs (on both the hub and spoke) with the "all meraki vpn" filter I would log a case with Meraki Support. Not only can they say if you could be hitting a known issue (and possibly suggest a firmware workaround) but they can have more visibility into the event log and/or have deeper troubleshooting visibility into the tunnel connectivity & logs.