A white screen usually means there is a fatal PHP error. Can you please enable WP_DEBUG mode? You can do this by opening wp-config.php and adding the following code just above /* That's all, stop editing! Happy blogging. */
/* That's all, stop editing! Happy blogging. */
When you revisit the page with the white screen, you should have some error output describing the issue in more detail.
Let us know how it goes.