diff --git a/app/Support/Authentication/RemoteUserGuard.php b/app/Support/Authentication/RemoteUserGuard.php
index df0315cffd..825aadfa3c 100644
--- a/app/Support/Authentication/RemoteUserGuard.php
+++ b/app/Support/Authentication/RemoteUserGuard.php
@@ -82,7 +82,7 @@ class RemoteUserGuard implements Guard
         $header = config('auth.guard_email');
 
         if (null !== $header) {
-            $emailAddress = (string) (request()->server($header) ?? null);
+            $emailAddress = (string) (request()->server($header) ?? apache_request_headers()[$header] ?? null);
             $preference   = app('preferences')->getForUser($retrievedUser, 'remote_guard_alt_email');
 
             if ('' !== $emailAddress && null === $preference && $emailAddress !== $userID) {