@GastonDC 

It does not sound like an issue to me with the router. It is your browse forcing HTTP to https. 

Search keywords like chrome/firefox force HTTP to https, you can see a lot of solutions. 

• Go to chrome://net-internals/#hsts.
• scroll down to the Delete domain security policies area.
• Type in the domain for which you want to prevent redirection. Click on Delete.

Then, go to history, and clear your cache in Clear Browsing data.. and make sure that you remove all cached files and cookies.

Now it should stop redirection from http to https only for that specific domain.

  @John1234 

First of all, thanks for your help.

The thing is the VPN is working fine with the ER6120 in my remote office and a TMG ( forefront firewall ) in my main office. this only happens when i make the VPN with the two ER6120.

Any other thing that i could try?