Epic Games Installer (error message) is already running but is not displayed in Task Manager or Desktop?

4 months ago I played Fortnite about the last time and then uninstalled it again due to lack of space. But since I have enough again I wanted to install it again, but when I started the EpicGamesInstaller download, the error message Epic Games Launcher was already running, close it to start the download. It is shown to me but neither in the Task Manager nor on the desktop that I have it running what can I do?

I already had this problem. For me, the Epic Games Launcher was active in the background processes