Hi Totophe56,
For me, the blank screen normally indicated a 500 server error where I had something not properly configured.
What version of Ilias is this for? Is this on Windows or Linux infrastructure? What type of database and engine did you select? Is this for all "clients" in Ilias? Please provide a brief overview of your infrastructure and ilias install.
Error Logs
You have 2 primary sets of error logs, one for Ilias and one for your web server (ie apache2, nginx, IIS, etc). Your Ilias error log file is defined during client setup in setup/setup.php . Take a peak in both your Ilias error log and your web server error log before and after getting the blank screen. You might see something in there.
Permissions
Confirm your permissions are properly set on your files / directories. If using linux, you will want the files to be in the same group as your web server (ie www-data or something like that).
Services
I am not sure if SOAP is required for the permissions tab, I highly doubt it, but it might be something to check. If you can call soap, then you can rule that one out.
Installation
During installation, a few php-* packages are required as well as a few other packages. Confirm those are all installed.
If you can provide a little more information about your install, the community will be able to point you in the right direction.
Regards,
Adam