Tracing a Login White Screen That Locked Every Administrator Out of a Learning Platform

The situation

Every administrator of a custom WordPress learning platform hit a white screen immediately after logging in. Nobody could reach the backend, so the site was effectively unmanageable while courses were live. The platform was not a standard WordPress build: it ran a bespoke session management layer loaded at the very top of wp-config.php, before WordPress itself, which set critical parameters including the database table prefix. That custom architecture made the usual white-screen checklist useless.

What I did

I worked through the site’s boot sequence rather than guessing at plugins. The custom session file had to execute correctly before anything else, because if it failed, the table prefix was never set and WordPress died silently. I then traced the login path and found the custom login template nested a standard WordPress login form inside its own logic, creating two competing authentication flows.

The root cause turned out to be a third-party LearnDash companion plugin whose login function used a non-standard authentication method incompatible with the site’s early session initialization. During the engagement I also confirmed the plugin vendor had just shipped an update whose release notes described exactly this failure, admins redirected to a blank page on login. With the conflict isolated and understood, applying that update resolved the issue permanently rather than masking it.

The outcome

Administrative access was restored and the client came away knowing precisely why their site broke: a documented interaction between their custom session layer and one plugin’s login shortcut. On heavily customized platforms, the diagnosis is the deliverable. Anyone can toggle plugins off. Knowing which layer of a bespoke boot sequence failed, and why, is what prevents the next outage.