Both database errors and PHP errors can cause the famous “White Screen Of Death (WSOD)”. This is when your WordPress site is returning no information, just a blank screen.
There are two main reasons for this happening, and happily they are quite easy to put right.

Plugin conflict or compatability issue
Firstly, the WSOD can be caused by a plugin causing compatability issues. If you are still able to log in to your admin area, deactivate all of your plugins and see if this solves the problem. If it does, turn your plugins back on, one at a time, in order to isolate the plugin that is causing the issue. You can then either contact the plugin creator, or look for an alternative plugin that doesn’t cause the conflict.
If you are unable to log in to your admin area, then access your site via ftp and rename your plugins folder to plugins_old. This will disable all of your plugins, and allow you to log back in. Once you are in the admin area, disable all of your plugins, as above. Rename the plugins_old folder back to plugins, and activate them in the admin area one at a time to isolate the problem plugin, as above.

Theme conflict or compatability issue
An issue with the theme is a common cause of the WSOD after you have activated a new theme or created a new site in the WordPress Network.
If you are able to log in to the admin area, switch the theme to a default theme, for example the WordPress Twenty Sixteen theme. You will then need to contact the problem theme’s creator, or choose another theme to use.
If you are unable to log in to the admin area, then access your site via ftp, and rename the theme folder for the active theme. This will disable the theme and allow to log in and switch to a default theme.

Help! It still doesn’t work!
The vast majority of the time the above solutions will fix the issue, however, if you are still stuck with the WSOD, then you can contact us for help.