When I want to start ICQ there is a "Hoppla da lief was schief" message. This is happening only on my user ID. I can connect with my sister username. What can I do?
The message indicates that something went wrong. In order to fix the problem, I suggest you use the Forgot Password page to reset the password of your account. If this doesn't help, remove the software from your computer (Control Panel > Uninstall a program), run CCleaner or Glary Utilities and download and install the latest version of the program from the official web page. Also, configure your security program and Windows Firewall to allow ICQ to communicate.