Hi,
after presenting the mysql credentials, the setups force closes. I tried to manually start apache webserver. Error was that it cannot find ssl files mentioned in the config file. I doublechecked via sftp. Folder /var/www/imscp/gui/data/certs is missing. I disabled every ssl site by a2dissite "config file with _ssl". After that the setup did finish without errors. certificate folder is back and apache virtual hosts are activated automaticly.