Phase2 VPN dropping
We have a number of subnets between 2 site to site VPNs and we are seeing the occasional phase 2 drop, or hang. Both firewalls are showing the connection up, but traffic isn't passing. Hitting the renegotiate button resolves the issue. This has caused some significant distress, and we missed it the first couple of times troubleshooting, because everything is showing up and running in the firewall GUI. Other phase 2 connections on the same VPN Policy remain connected.
I'm looking for what to troubleshoot so we can avoid these outages.
VPNs between NSa 3650 and NSa 4600, both running SonicOS Enhanced 18.104.22.168-79n