Hello,
A PHP error occurs if a blank page appears. It can occurs if PHP memory limit is exhausted or for other reason. Try to set temporary "System -> Global Configuration -> Server -> Error Reporting" parameter on Joomla! backend to "Development" value to see what error occurs and send it to us so we can provide a solution how to fix the problem or provide a link to a page where the problem occurs and a temporary access to your J! backend by
email so we can investigate the problem.
Regards,
ARI Soft