Hi, we have had the same problem for several days: a blank white screen.
Our hosting service could not solve the problem.
By changing "Error Reporting" to Maximum there is an error:
Fatal error: Class 'ObjectExtendable' not found in /web/htdocs/www.xxxxxxxxxxxxx.net/home/plugins/system/t3/includes/core/template.php on line 26
PLEASE, HELP US!!!