I want to start by saying that I love this game and Emilie is a total darling and MC is, at least according to my decisions, a bit of a legend.
Now I fully recognise that this may be because I'm missing something, I have missed something or am simply not clever enough but I can't get through the bloody server sequence with Natacha and Iris. I've gone through it a dozen times and I can't see what it is I'm missing out.
I get the reason for not having a walkthrough and I can see that the game could ... can go off in a hundred different directions
So, it's not obvious, but I think what you're likely missing is that there are hidden files in the file explorer that can be revealed by clicking the 'show hidden files' button. I didn't realise it would work properly either.
If that doesn't work, you just need to search through the emails with the right keywords. I won't post them here due to spoilers, but everything you need is provided in the section.
Oh, and the security cameras, but I figure those are the obvious ones.