I’ve just had a bunch of work sites throw the dreaded White Screen of Death (WSoD). Turns out it’s the custom permalinks (3rd party) plugin. As soon as a site updated to 7.2.2 (from memory) – boom! no site.
So just remove that plugin for the moment and chances are your site will be back up.
Caveats: If you need that plugin you need to wait for the next update in the hope it’ll fix it, or fin an alternative, and the chances this plugin are the reason your site is down will probably decrease from now 😉