I’m sharing this in case anyone else encounters a similar issue. I spent hours searching for a solution related to GOG without any success. Eventually, I discovered the fix after Discord suddenly stopped working post-restart. Interestingly, all other applications, including Steam and the internet, functioned perfectly.

My GOG Galaxy suddenly stopped connecting to the internet, consistently claiming that I had no connection.

I tried several troubleshooting steps, but nothing worked. I ended up reinstalling the application, but it still didn't work, and it now won't let me log in either.

After reinstalling, I noticed that Discord had also stopped working. I disabled my firewall, checked my router, and turned off my anti-virus (Kaspersky), but to no avail. Then I found a fix that resolved both the Discord and GOG Galaxy 2.0 issues:

1) Disable Self-Defense via Settings -> General
2) Exit Kaspersky product
3) Go to folder C:\ProgramData\Kaspersky Lab\AVP21.3\Report\ and delete all the contents (files and folders)
4) Run Kaspersky product
5) Enable Self-Defense
6) Check the issue (mine was resolved for Discord and GOG Galaxy)

After performing these steps, I could log in to GOG Galaxy again. However, I had to reconfigure everything since I had tried deleting profiles. Sigh.

You should probably post that in the Galaxy forum: https://www.gog.com/forum/general_beta_gog_galaxy_2.0

In fairness this is not a GOG problem.

You should post this on the Kaspersky forum and be irritated that they don't pay you for helping their users.

Step 1: uninstall Kaspersky
Step 2: profit
Step 3: there is no step 3