I'm having troubles with routing LAN-to-REMOTE_LAN traffic through HA/Wireguard recently (after working without a burp for a year or so). I have three HA instances, two of which are connected through Wireguard (Add-on), the third is still on the OpenVPN provided by network routers/firewalls, waiting for me to solve the problems I'm having with the first two to jump over to the same config. Let's name the relevant HA installations as HOME_HA and REMOTE_HA, relevant networks as HOME_LAN and REMOTE_LAN.
Both of the HAs in question are "HassOS" method of installation on two identical Intel NUCs (Pentium Silver J5005). I have/had them provide site-to-site connectivity and sometime in the last month or so the client connectivity died. Nothing in the HOME or REMOTE location has changes, so my thoughts are - it must be something in the HA / Wireguard Add-on must have changed.
Both of the HA instances can connect to the remote LAN clients (remote storage/backup), "just" the LAN clients can't. Also, I have a peer config in both of the HA instances' Wireguard Add-ons for me to be able to connect to both LANs for testing / "support" purposes. When I connect with my phone, I can connect to both the respective LAN clients and HA instances.
My tests uptodate. Ping HOME_HA <-> REMOTE_HA ✅ , ping HOME_HA -> REMOTE_LAN client ✅ , ping HOME_LAN client -> REMOTE_HA ❌, HOME_LAN client -> REMOTE_LAN client ❌ . Ping REMOTE_LAN client -> HOME_HA ❌, REMOTE_LAN client -> HOME_LAN client ❌ . Traceroute HOME_LAN client -> REMOTE_HA makes the hops it's supposed to (local router/firewall -> HOME_HA), but times out when it reaches HOME_HA (third hop); the same is true for REMOTE. Traceroute from HOME_HA - REMOTE_HA shows traffic is routed through Wireguard Add-on (docker) and reaches REMOTE_HA, same for REMOTE.
Could anyone please help me with diagnosing/fixing the problem? If needed, can post relevant configs, just didn't want to scare people off with a wall of text.
Thanks in advance