When updating or installing new plug-ins or themes a white screen can occur.
To start troubleshooting to help find the cause you can do the following:

Open an FTP Client like Filezilla
Connect to your Website through FTP
Go to: <root>WP-Content\Themes\
Rename Theme Directory so there is no “-“ in it
Rename “Plugins” Folder to “Plugins_Old”.
Create new empty folder called “plugins”
This will disable all the WordPress plugins.
Log into WordPress and verify that you no longer have the White Screen
Make sure all plugins are disabled.
Delete “plugins” folder you just created.
Rename “plugins_old” to “plugins”.
Log back into WordPress
Enable plug-ins one at a time to see which one is causing the issue.

NOTE: Be sure to re-enable plugins and themes one at a time to find the one that caused the issue.