diff --git a/nixos/modules/services/web-apps/powerdns-admin.nix b/nixos/modules/services/web-apps/powerdns-admin.nix
index 7c23cd10efad..e142711555ca 100644
--- a/nixos/modules/services/web-apps/powerdns-admin.nix
+++ b/nixos/modules/services/web-apps/powerdns-admin.nix
@@ -42,14 +42,21 @@ in
       type = types.str;
       default = "";
       example = ''
+        import cachelib
+
         BIND_ADDRESS = '127.0.0.1'
         PORT = 8000
         SQLALCHEMY_DATABASE_URI = 'postgresql://powerdnsadmin@/powerdnsadmin?host=/run/postgresql'
+        SESSION_TYPE = 'cachelib'
+        SESSION_CACHELIB = cachelib.simple.SimpleCache()
       '';
       description = ''
         Configuration python file.
         See [the example configuration](https://github.com/ngoduykhanh/PowerDNS-Admin/blob/v${pkgs.powerdns-admin.version}/configs/development.py)
         for options.
+        Also see [Flask Session configuration](https://flask-session.readthedocs.io/en/latest/config.html#SESSION_TYPE)
+        as the version shipped with NixOS is more recent than the one PowerDNS-Admin expects
+        and it requires explicit configuration.
       '';
     };
 
@@ -85,7 +92,7 @@ in
       serviceConfig = {
         ExecStart = "${pkgs.powerdns-admin}/bin/powerdns-admin --pid /run/powerdns-admin/pid ${escapeShellArgs cfg.extraArgs}";
         # Set environment variables only for starting flask database upgrade
-        ExecStartPre = "${pkgs.coreutils}/bin/env FLASK_APP=${pkgs.powerdns-admin}/share/powerdnsadmin/__init__.py SESSION_TYPE= ${pkgs.python3Packages.flask}/bin/flask db upgrade -d ${pkgs.powerdns-admin}/share/migrations";
+        ExecStartPre = "${pkgs.coreutils}/bin/env FLASK_APP=${pkgs.powerdns-admin}/share/powerdnsadmin/__init__.py ${pkgs.python3Packages.flask}/bin/flask db upgrade -d ${pkgs.powerdns-admin}/share/migrations";
         ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
         ExecStop = "${pkgs.coreutils}/bin/kill -TERM $MAINPID";
         PIDFile = "/run/powerdns-admin/pid";
diff --git a/nixos/tests/powerdns-admin.nix b/nixos/tests/powerdns-admin.nix
index 1f9354927acd..0ed31f46607f 100644
--- a/nixos/tests/powerdns-admin.nix
+++ b/nixos/tests/powerdns-admin.nix
@@ -9,9 +9,13 @@ with import ../lib/testing-python.nix { inherit system pkgs; };
 with pkgs.lib;
 let
   defaultConfig = ''
+    import cachelib
+
     BIND_ADDRESS = '127.0.0.1'
     PORT = 8000
     CAPTCHA_ENABLE = False
+    SESSION_TYPE = 'cachelib'
+    SESSION_CACHELIB = cachelib.simple.SimpleCache()
   '';
 
   makeAppTest =