diff --git a/TwoFactorAuth/Model/Provider/Engine/DuoSecurity.php b/TwoFactorAuth/Model/Provider/Engine/DuoSecurity.php
index 5ede11be..394bf60b 100644
--- a/TwoFactorAuth/Model/Provider/Engine/DuoSecurity.php
+++ b/TwoFactorAuth/Model/Provider/Engine/DuoSecurity.php
@@ -196,7 +196,11 @@ public function verify(UserInterface $user, DataObject $request): bool
     private function isDuoForcedProvider(): bool
     {
         $providers = $this->scopeConfig->getValue('twofactorauth/general/force_providers') ?? '';
-        $forcedProviders = array_map('trim', explode(',', $providers));
+        if (is_array($providers)) {
+            $forcedProviders = array_map('trim', $providers);
+        } else {
+            $forcedProviders = array_map('trim', explode(',', (string)$providers));
+        }
         return in_array(self::CODE, $forcedProviders, true);
     }