Issues connecting from the Pgadmin4 QueryTool over a VPN connection

I upgraded from pgadmin III to pgadmin4. I have installed it on a Windows 10 environment and I use a chrome browser.

Sometimes I work remotely (over OpenVPN), previously with pgadmin III without problems.

Now I have a problem. Pgadmin4 is connecting (locally and remotely over VPN) OK to servers and databases, but, the QueryTool is not connecting (the problem happens only when trying to access over VPN, locally it connects). After starting the QueryToll, the connection symbol (upper left) is not marking a successful connection.

I guess this could be related to the route the QueryTool is taking in order to access the DB server or perhaps a timeout (my connection can be slow)? The Pgadmin4 interface in the browser connects without issues, only the QueryTool fails to do so. Any hints or ideas to solve or overcome this?