If you are a seeing a white screen front-end there may be an error message in your server’s error log that can provide a clue to what the problem is. Can you look in your server’s error log to see if it contains any clues?
It is difficult for us to know why you are getting a white screen. It could be that WordPress has run out of memory, or it could be a plugin conflict, or it could be server related… It could be a number of things.
Have you talked to your web hosts about this? They may be able to shed some light on the issue.
Let us know what you find in your server’s error log.