diff --git a/library/Icinga/Application/Modules/Manager.php b/library/Icinga/Application/Modules/Manager.php
index 55d074d70..9114f3ad4 100644
--- a/library/Icinga/Application/Modules/Manager.php
+++ b/library/Icinga/Application/Modules/Manager.php
@@ -3,6 +3,7 @@
 
 namespace Icinga\Application\Modules;
 
+use Fiber;
 use Icinga\Application\ApplicationBootstrap;
 use Icinga\Application\Icinga;
 use Icinga\Application\Logger;
@@ -187,8 +188,16 @@ class Manager
     public function loadEnabledModules()
     {
         if (! $this->loadedAllEnabledModules) {
+            $async = ! $this->app->isCli();
             foreach ($this->listEnabledModules() as $name) {
-                $this->loadModule($name);
+                if ($async) {
+                    // May be suspended during authentication and resumed upon finish
+                    (new Fiber(function () use ($name) {
+                        $this->loadModule($name);
+                    }))->start();
+                } else {
+                    $this->loadModule($name);
+                }
             }
 
             $this->loadedAllEnabledModules = true;
diff --git a/library/Icinga/Authentication/Auth.php b/library/Icinga/Authentication/Auth.php
index c2fbbeb4f..ee4deac1c 100644
--- a/library/Icinga/Authentication/Auth.php
+++ b/library/Icinga/Authentication/Auth.php
@@ -4,6 +4,7 @@
 namespace Icinga\Authentication;
 
 use Exception;
+use Fiber;
 use Icinga\Application\Config;
 use Icinga\Application\Hook\AuditHook;
 use Icinga\Application\Icinga;
@@ -59,6 +60,15 @@ class Auth
      */
     private bool $authenticated = false;
 
+    /**
+     * Fibers that were suspended during authentication
+     *
+     * This is used to resume fibers after authentication has been performed.
+     *
+     * @var Fiber[]
+     */
+    private array $suspendedFibers = [];
+
     /**
      * @see getInstance()
      */
@@ -97,7 +107,13 @@ class Auth
     public function isAuthenticated()
     {
         if (! $this->authenticated) {
-            trigger_error('Authentication can no longer be triggered implicitly', E_USER_DEPRECATED);
+            $fiber = Fiber::getCurrent();
+            if ($fiber !== null) {
+                $this->suspendedFibers[] = $fiber;
+                Fiber::suspend();
+            } else {
+                trigger_error('Authentication can no longer be triggered implicitly', E_USER_DEPRECATED);
+            }
         }
 
         return $this->user !== null;
@@ -250,6 +266,13 @@ class Auth
 
         $this->authenticated = true;
 
+        foreach ($this->suspendedFibers as $fiber) {
+            // Resume all suspended fibers
+            $fiber->resume();
+        }
+
+        $this->suspendedFibers = [];
+
         return $this;
     }