diff --git a/src/api/auth.js b/src/api/auth.js
index 5c37109..fd45a26 100644
--- a/src/api/auth.js
+++ b/src/api/auth.js
@@ -67,6 +67,7 @@ export async function logout(store) {
           application: TRYTON_APPLICATION,
         },
         includeKitchen: false,
+        skipAuthFailureHandler: true,
       });
     }
   } finally {
diff --git a/src/api/client.js b/src/api/client.js
index 0a01ffb..323aa2a 100644
--- a/src/api/client.js
+++ b/src/api/client.js
@@ -183,6 +183,32 @@ function logApiFailure(message, context) {
   console.error(message, context);
 }
 
+function isAuthErrorStatus(status) {
+  return status === 401 || status === 403;
+}
+
+function isKitchensPath(path) {
+  return String(path || '').replace(/^\/+/, '').replace(/\/+$/, '') === API_PATHS.kitchens;
+}
+
+function shouldInvalidateValidatedSession(store, path, options = {}) {
+  if (options.skipAuthFailureHandler) {
+    return false;
+  }
+
+  if (!store.session?.applicationKey || !store.session?.hasValidated) {
+    return false;
+  }
+
+  return (
+    isKitchensPath(path) ||
+    options.includeKitchen !== false ||
+    path === API_PATHS.items ||
+    path === API_PATHS.locations ||
+    String(path || '').startsWith(`${API_PATHS.items}/`)
+  );
+}
+
 export async function apiRequest(store, path, options = {}) {
   const { config, session, activeKitchen } = store;
 
@@ -240,6 +266,9 @@ export async function apiRequest(store, path, options = {}) {
       method,
       error,
     });
+    if (shouldInvalidateValidatedSession(store, path, options)) {
+      window.__loncApp?.handleAuthFailure?.(networkError);
+    }
     throw networkError;
   }
 
@@ -252,6 +281,15 @@ export async function apiRequest(store, path, options = {}) {
       status: response.status,
       payload,
     });
+    if (
+      isAuthErrorStatus(response.status) &&
+      (
+        shouldInvalidateValidatedSession(store, path, options) ||
+        (store.session?.state === 'connected' && response.status === 403 && isKitchensPath(path))
+      )
+    ) {
+      window.__loncApp?.handleAuthFailure?.(apiError);
+    }
     throw apiError;
   }
 
diff --git a/src/app/bootstrap.js b/src/app/bootstrap.js
index d034f68..576792a 100644
--- a/src/app/bootstrap.js
+++ b/src/app/bootstrap.js
@@ -44,6 +44,7 @@ export function bootstrapApp() {
     store,
     outlet: document.querySelector('#route-view'),
   });
+  let authFailureHandled = false;
 
   function applyKitchens(kitchens) {
     store.setKitchens(kitchens);
@@ -67,6 +68,9 @@ export function bootstrapApp() {
         } else if (store.isConnected) {
           await window.__loncApp.refreshKitchens();
         }
+        if (store.isConnected) {
+          authFailureHandled = false;
+        }
         renderNav();
       } catch (error) {
         renderNav();
@@ -82,11 +86,36 @@ export function bootstrapApp() {
       } else if (store.isConnected) {
         await window.__loncApp.refreshKitchens();
       }
+      if (store.isConnected) {
+        authFailureHandled = false;
+      }
       renderNav();
       return result;
     },
+    handleAuthFailure(error) {
+      if (!store.session?.applicationKey || !store.session?.hasValidated || authFailureHandled) {
+        return;
+      }
+
+      authFailureHandled = true;
+      store.markSessionInvalid();
+      renderNav();
+      const status = error?.status || error?.cause?.status;
+      const message =
+        status === 401 || status === 403
+          ? 'This application key is no longer accepted by Tryton. Please verify it again or disconnect and create a new key.'
+          : 'Authenticated requests are no longer succeeding. The application key may have been cancelled, or access is being denied by the server. Please reconnect or create a new key.';
+      store.addAlert({
+        type: 'warning',
+        timeout: 0,
+        message,
+      });
+      navigate('/login');
+      window.setTimeout(() => router.render(), 0);
+    },
     async logout() {
       await logout(store);
+      authFailureHandled = false;
       renderNav();
       navigate('/login');
     },
diff --git a/src/app/store.js b/src/app/store.js
index 49132b0..10ee154 100644
--- a/src/app/store.js
+++ b/src/app/store.js
@@ -108,5 +108,18 @@ export function createAppStore() {
       this.setKitchens([]);
       this.setActiveKitchen(null);
     },
+    markSessionInvalid() {
+      if (!this.session) {
+        return;
+      }
+
+      this.setSession({
+        ...this.session,
+        state: CONNECTION_STATES.invalidKey,
+        hasValidated: true,
+      });
+      this.setKitchens([]);
+      this.setActiveKitchen(null);
+    },
   };
 }
diff --git a/src/features/labels/label-create-page.js b/src/features/labels/label-create-page.js
index 9fc7bf7..e9faadc 100644
--- a/src/features/labels/label-create-page.js
+++ b/src/features/labels/label-create-page.js
@@ -515,6 +515,9 @@ export function labelCreatePageData(store) {
       ...loadLabelDraft(),
     },
     async init() {
+      if (!store.isConnected) {
+        return;
+      }
       await this.loadLocations();
       this.$watch('form', () => this.persistDraft(), { deep: true });
       this.$watch('form.stockType', (value) => {
@@ -536,6 +539,10 @@ export function labelCreatePageData(store) {
       }, 250);
     },
     async loadLocations() {
+      if (!store.isConnected) {
+        return;
+      }
+
       try {
         const { flat } = await fetchLocations(store);
         this.locations = flat;
diff --git a/src/features/stock/stock-detail-page.js b/src/features/stock/stock-detail-page.js
index 4f9886b..dd0af21 100644
--- a/src/features/stock/stock-detail-page.js
+++ b/src/features/stock/stock-detail-page.js
@@ -152,6 +152,10 @@ export function stockDetailPageData(store) {
       level: 'plenty',
     },
     async init() {
+      if (!store.isConnected) {
+        return;
+      }
+
       const { params } = getRouteContext();
       await runAsyncState(this.state, async () => {
         this.entry = await getStockEntry(store, params.id);
diff --git a/src/features/stock/stock-list-page.js b/src/features/stock/stock-list-page.js
index 25d7cd5..fc5677d 100644
--- a/src/features/stock/stock-list-page.js
+++ b/src/features/stock/stock-list-page.js
@@ -442,9 +442,16 @@ export function stockListPageData(store) {
       location: '',
     },
     async init() {
+      if (!store.isConnected) {
+        return;
+      }
       await Promise.all([this.loadLocations(), this.loadEntries()]);
     },
     async loadEntries() {
+      if (!store.isConnected) {
+        return;
+      }
+
       await runAsyncState(this.state, async () => {
         const loadedEntries = await listStockEntries(store);
         this.entries = sortEntries(loadedEntries);
@@ -461,6 +468,10 @@ export function stockListPageData(store) {
       }).catch(() => {});
     },
     async loadLocations() {
+      if (!store.isConnected) {
+        return;
+      }
+
       try {
         const { flat } = await fetchLocations(store);
         this.locations = flat;