Enable installer debugging
Sometimes the install process might give you headaches, though this is extremely rare, it seems it can happen. It can be because importing the database schema takes too much time, or because you lose the session in middle of the install, or for any various other things.
In order to enable debugging for this process, open the file install/index.php and look for the lines:
// since this is production, stay silent ini_set('display_errors', 0); error_reporting(0);
And make them:
// since this is production, stay silent ini_set('display_errors', 1); error_reporting(-1);
Then save the file and try the installer again, this time if you have any issue, you should see the actual error message.
Please note that if your server times out during database import, there’s not much MailWizz can do to help you, just contact you hosting provider to help you go through the issue.