Index: src/helper/backend/PamBackend.cpp
--- src/helper/backend/PamBackend.cpp.orig
+++ src/helper/backend/PamBackend.cpp
@@ -219,7 +219,7 @@ namespace SDDM {
 
         QString service = QStringLiteral("sddm");
 
-        if (user == QStringLiteral("sddm") && m_greeter)
+        if (user == QStringLiteral("_sddm") && m_greeter)
             service = QStringLiteral("sddm-greeter");
         else if (m_autologin)
             service = QStringLiteral("sddm-autologin");
