@valentinprgnd The FAB plugin has been buggy for a long time. Depending on the directory where your game project is located, the plugin can bug out and stop working. Try creating your project in the default Unreal project folder. If that doesn’t work either, your only option might be to use the FAB plugin in one of Unreal Engine’s template projects and migrate content in ur real project — that worked in my case.
I did extensive testing and checked the logs for many many hours. The plugin seems especially buggy for new users who don’t use the default project path. Unfortunately, Epic Games doesn’t seem to consider the FAB plugin important for the developer experience and probably won’t fix this long-standing issue. Every period of time people like u and me come to the Forum with this Issue.