diff --git a/DigitalData.UserManager.API/ClientApp/user_manager_ui/src/environments/environment.prod.ts b/DigitalData.UserManager.API/ClientApp/user_manager_ui/src/environments/environment.prod.ts
index 591410b9..24feb89 100644
--- a/DigitalData.UserManager.API/ClientApp/user_manager_ui/src/environments/environment.prod.ts
+++ b/DigitalData.UserManager.API/ClientApp/user_manager_ui/src/environments/environment.prod.ts
@@ -165,6 +165,14 @@ export const env = {
                 header: "Repr. Benutzer",
                 field: (ur: any) => ur.repUser?.username
             },
+            {
+                header: "Gültig von",
+                field: (ur: any) => ur.validFrom ? new Date(ur.validFrom).toLocaleDateString('de-DE') : ""
+            },
+            {
+                header: "Gültig bis",
+                field: (ur: any) => ur.validTo ? new Date(ur.validTo).toLocaleDateString('de-DE') : ""
+            }
         ]
     },
     config_url: "/assets/config.json",
diff --git a/DigitalData.UserManager.API/ClientApp/user_manager_ui/src/environments/environment.ts b/DigitalData.UserManager.API/ClientApp/user_manager_ui/src/environments/environment.ts
index be71944..24feb89 100644
--- a/DigitalData.UserManager.API/ClientApp/user_manager_ui/src/environments/environment.ts
+++ b/DigitalData.UserManager.API/ClientApp/user_manager_ui/src/environments/environment.ts
@@ -167,11 +167,11 @@ export const env = {
             },
             {
                 header: "Gültig von",
-                field: (ur: any) => new Date(ur.validFrom).toLocaleDateString('de-DE')
+                field: (ur: any) => ur.validFrom ? new Date(ur.validFrom).toLocaleDateString('de-DE') : ""
             },
             {
                 header: "Gültig bis",
-                field: (ur: any) => new Date(ur.validTo).toLocaleDateString('de-DE')
+                field: (ur: any) => ur.validTo ? new Date(ur.validTo).toLocaleDateString('de-DE') : ""
             }
         ]
     },
@@ -196,4 +196,4 @@ export const env = {
             { value: "en-US", name: "en-US" }
         ]
     }
-};
+};
\ No newline at end of file