Game does not start. Instead I get a window with the message
'The server is not reachable. Check your Internet connection and click "Retry"
In case the problem persists, click "Next" to open the support website in the default browser'
The next window where I have manually to open the website doesn't show the code, so I can't proceed with the manual method.
Compatibility Report
System Information
I confirm:
steam-1237320.log
Symptoms
Game does not start. Instead I get a window with the message
'The server is not reachable. Check your Internet connection and click "Retry"

In case the problem persists, click "Next" to open the support website in the default browser'
The next window where I have manually to open the website doesn't show the code, so I can't proceed with the manual method.

Reproduction
Starting the game