Error trying to update database after module update After I update a module, and click at http://omroepzuidplas.nl/admin/update/ready on the 'run' button to do the database updates. Drupal sends me to this url:

http://omroepzuidplas.nl/http%253A//omroepzuidplas.nl/authorize.php%3Fbatch%3D1?op=start&amp;id=2796

Which result in an 404 page not found error. 

I use Drupal 7.50 on CentOS7.
The problem you are having is likely either that the RewriteBase is not set in .htaccess, or the base_url is not set in settings.php.  Likely you can bypass the settings problem if you go directly to http://omroepzuidplas.nl/update.php. 

To do database updates you have to be logged in as User 1 (often called admin or super admin, but it could have any user name).