firefox driver connect to existing firefox

[bjm3...@gmail.com]

Hello

I am beginning with selenium (migrating from mshtml) and as usual the start is not the easiest.

I want to open Firefox, navigate some places manually  and then start automation.

I try to decompose all steps to understand what is going on.

1) I start Selenium server (in a batch file). up and running

2) Then I start Firefox with the -marionette option (in a .bat file). The window opens I can navigate, so far so good.

3) Then I want to start geckodriver : geckodriver.exe --connect-existing --marionette-port 2828 (in a .bat file)

to connect to the previous Firefox

but I get message 

geckodriver.exe: error: Une tentative d’accès à un socket de manière interdite par ses "autorisations d’accès a été tentée. (os error 10013)

geckodriver 0.26.0 (e9783a644016 2019-10-10 13:38 +0000)

WebDriver implementation for Firefox"

saying that this is forbidden.

4) with Firefox, Selenium server and Geockdriver running I would then start automation using VB code in Visual studio.

can somebody help me get started ?

thanks in advance