diff --git a/modules/ipa/client.nix b/modules/ipa/client.nix
index 818400c..3880be2 100644
--- a/modules/ipa/client.nix
+++ b/modules/ipa/client.nix
@@ -60,6 +60,15 @@ lib.mkIf enabled {
     pam.services = {
       sshd.makeHomeDir = true;
       lightdm.makeHomeDir = true;
+
+      # pam_unix returns PAM_AUTHINFO_UNAVAIL without prompting when the local
+      # stub has "!" in shadow (account locked), so PAM_AUTHTOK is never set
+      # and pam_sss's use_first_pass fails with "No authentication token".
+      # Changing to try_first_pass makes pam_sss prompt independently when no
+      # prior module has set the token, restoring IPA password login via
+      # LightDM and su.
+      login.rules.auth.sss.settings = lib.mkForce { try_first_pass = true; };
+      su.rules.auth.sss.settings = lib.mkForce { try_first_pass = true; };
     };
 
     # HM with useUserPackages = true (flake.nix) sets users.users.${ipaUser}.packages,
@@ -170,6 +179,13 @@ lib.mkIf enabled {
     group = "users";
     extraGroups = [ "wheel" ];
     createHome = false;
+    # "!" is not a password hash — it is the standard "account locked" marker.
+    # It cannot authenticate anyone locally. It exists solely so NixOS generates
+    # a shadow entry for this stub user; without one pam_unix returns
+    # PAM_AUTHINFO_UNAVAIL before prompting, which means PAM_AUTHTOK is never
+    # set and the subsequent pam_sss use_first_pass call has nothing to work
+    # with — blocking LightDM and su logins even when IPA/SSSD auth succeeds.
+    hashedPassword = "!";
   };
 
   # Home Manager config for the IPA primary user, applied on every enrolled