WebGui not accessible via OpenVPN

[gdur]

I'm setting up a new server which is connected to a new fiber provider to replace an existing old server still operational connected to a different fiber provider.
Instead of using a backup from the old machine I want to set-up the new machine from scratch.
I have configured the LAN port of the new machine with a fixed IP address in the same subnet as the LAN of the "old" machine in order to have both WebGui's in sight while copying settings and rules from the "old" to the "new" machine. This works flawless from my workplace in the office being connected to another subnet on the "old" machine.
Once connecting to the "old" machine via OpenVPN there is no response from the WebGui of the "new" machine so traffic is somewhere blocked but while looking at the life logs on both machines it is clear that the request is passing through bot firewalls. The only possible related error I found in the general log of the new machine saying "Error   lighttpd   (/usr/obj/usr/ports/www/lighttpd/work/lighttpd-1.4.76/src/mod_openssl.c.3510) SSL: 1 error:0A00009C:SSL routines::http request (10.67.6.102)" .
So obviously this is the webserver not accepting the request.
Does anyone understands this lighttpd error and what can be done to overcome?

Another question is the following:
My new connection is 1Gbit opposed to 50Mbit of the old one so I'd like to use the available speed of this new connection through the "old" server while setting up this new firewall. What would be the best solution to route web traffic through this high speed connection.

[gstrauss]

> "Error   lighttpd   (/usr/obj/usr/ports/www/lighttpd/work/lighttpd-1.4.76/src/mod_openssl.c.3510) SSL: 1 error:0A00009C:SSL routines::http request (10.67.6.102)

That suggests that you made an HTTP (clear-text ) request to a port on which lighttpd was configured to expect HTTPS (TLS).

Or maybe you misconfigured your lighttpd.conf to have lighttpd expect TLS on port 80, so when you made an HTTP (clear-text) request to port 80, it failed as above.