How to solve the problem with nginx proxy + ipsec?

Question

Nginx

There is an odoo 9 server with http on port 8069. Traffic goes over https through nginx proxy.
From the internal network everything works fine, from remote networks via open connect too.
And here from other network through ipsec (site to site) a problem. The login page and the first page open, but then the server does not seem to respond to ajax requests. At the same time, there is nothing in the odoo logs or in the nginx logs.
If you go directly like http://[ip address]:8069 everything is ok. Those. The problem is in nginx. Where to dig?

Answer 1

Somewhere something is not natitsya or is not routed. Nginx knows nothing about your tunnels and IPsecs.
We need consistent diagnostics with a traffic dump and smoking network settings.