diff --git a/gradle/changelog/namespace_not_existing.yaml b/gradle/changelog/namespace_not_existing.yaml
new file mode 100644
index 0000000000..fac7f3b410
--- /dev/null
+++ b/gradle/changelog/namespace_not_existing.yaml
@@ -0,0 +1,2 @@
+- type: fixed
+  description: Do not show repositories on overview for not existing namespace ([#1608](https://github.com/scm-manager/scm-manager/pull/1608))
diff --git a/scm-ui/ui-webapp/public/locales/de/repos.json b/scm-ui/ui-webapp/public/locales/de/repos.json
index 2a7c5f5d6c..091cfa1d14 100644
--- a/scm-ui/ui-webapp/public/locales/de/repos.json
+++ b/scm-ui/ui-webapp/public/locales/de/repos.json
@@ -56,6 +56,7 @@
     "title": "Repositories",
     "subtitle": "Übersicht aller verfügbaren Repositories",
     "noRepositories": "Keine Repositories gefunden.",
+    "invalidNamespace": "Keine Repositories gefunden. Möglicherweise existiert der ausgewählte Namespace nicht.",
     "createButton": "Repository hinzufügen",
     "searchRepository": "Repository suchen",
     "allNamespaces": "Alle Namespaces"
diff --git a/scm-ui/ui-webapp/public/locales/en/repos.json b/scm-ui/ui-webapp/public/locales/en/repos.json
index b8635d9385..9a46680807 100644
--- a/scm-ui/ui-webapp/public/locales/en/repos.json
+++ b/scm-ui/ui-webapp/public/locales/en/repos.json
@@ -56,6 +56,7 @@
     "title": "Repositories",
     "subtitle": "Overview of available repositories",
     "noRepositories": "No repositories found.",
+    "invalidNamespace": "No repositories found. It's likely that the selected namespace does not exist.",
     "createButton": "Add Repository",
     "searchRepository": "Search repository",
     "allNamespaces": "All namespaces"
diff --git a/scm-ui/ui-webapp/src/repos/containers/Overview.tsx b/scm-ui/ui-webapp/src/repos/containers/Overview.tsx
index ba374fbae5..66d8275dd1 100644
--- a/scm-ui/ui-webapp/src/repos/containers/Overview.tsx
+++ b/scm-ui/ui-webapp/src/repos/containers/Overview.tsx
@@ -56,7 +56,10 @@ const useOverviewData = () => {
     search,
     // if a namespaces is selected we have to wait
     // until the list of namespaces are loaded from the server
-    disabled: !!namespace && !namespaces
+    // also do not fetch repositories if an invalid namespace is selected
+    disabled:
+      (!!namespace && !namespaces) ||
+      (!!namespace && !namespaces?._embedded.namespaces.some(n => n.namespace === namespace))
   };
   const { isLoading: isLoadingRepositories, error: errorRepositories, data: repositories } = useRepositories(request);
 
@@ -92,7 +95,7 @@ const Repositories: FC<RepositoriesProps> = ({ namespaces, repositories, search,
       return <Notification type="info">{t("overview.noRepositories")}</Notification>;
     }
   } else {
-    return null;
+    return <Notification type="info">{t("overview.invalidNamespace")}</Notification>;
   }
 };
 
@@ -141,7 +144,9 @@ const Overview: FC = () => {
         {showActions ? (
           <OverviewPageActions
             showCreateButton={showCreateButton}
-            currentGroup={namespace || ""}
+            currentGroup={
+              namespace && namespaces?._embedded.namespaces.some(n => n.namespace === namespace) ? namespace : ""
+            }
             groups={namespacesToRender}
             groupSelected={namespaceSelected}
             link={namespace ? `repos/${namespace}` : "repos"}