In that case something is, at least occasionally, blocking the launcher from accessing the internet for some reason.
I've had a similar problem with BitDefender. It would revoke the laucher's rights to access the internet so I could not start the game.
An anti-virus, or not running the launcher as admin, would be the most logical causes for that error to happen.
Again, all on the assumption I am interpreting the exceptions thrown in that error correctly, since I do not know the funtions they refer to.