Could not determine IPv4/IPv6 protocol. Using AF_INET + TLS handshake errors

[loganx1121]

I have 3 firewalls.  On one, I have multiple OpenVPN servers running, no issues.  On another, single OpenVPN instance running, no issues.  On the third, I can't seem to get it to work.

I keep seeing Could not determine IPv4/IPv6 protocol. Using AF_INET and TLS handshake errors in the OpenVPN logs.  On the dashboard of the firewall, under OpenVPN clients widget, I see the public IP of the location I'm trying to connect -from-, and no virtual IP.

I've compared the server settings with the other 2 firewalls and can't find a difference.  I've also deleted and recreated the CA, INT CA, Server and client certificates a handful of times now, and verified the associated firewall rules are identical for allowing the connection across all 3 firewalls.

Struggling to figure out why it works on the other two OPNSense firewalls but not this one. 

[loganx1121]

Did some more testing and found something interesting.

At one site, I can connect to OpenVPN fine from my desktop.  There's a wireguard tunnel between my site and this site.

At the site that isn't working, there is also a wireguard tunnel, setup the same way, same allowed IP configuration meaning I'm just allowing the entire /24 network in the tunnel.  I can't connect to the OpenVPN at that site from my desktop.

The interesting part, is if I RDP to a machine on a different VLAN, the OpenVPN connection works fine.  Thoroughly confused.