Hi, did you tried just to wait after the login?
Cause whenever I try to open the GG ingame store it takes arround 10-15 minutes till it opens. And nothing happens until that. till today I found no solution for this but just to wait.
I can confirm this.
My Crusader Kings 2 takes several minutes to load and once I try to get into the game store it freezes again looking like it has crashed. But waiting for around 10 Minutes will actually make the store appear. The next thing that happens is that I have to log in which again seems to take ages. (Not there yet) Depending how long this takes only gettingo to the list so that I can start to download the updates I bought took at the very least 30 minutes.
From expiriece I also can add to that that often the downloads will fail after they take ages to be proerly registered after the download which leads to having to restart the game in some cases.
Furtheremore when I start a new game the icons that show which pits of DLC are bought and active only show up partially, it seem though that they are all working.
Would be great if we knew the reason for this and if there was any way to speed this process up. The rest of the game at least on my computer runs and plays fine, but getting DLC become more and more unpleasant with each new step.