diff --git a/server/routes/auth.js b/server/routes/auth.js
index 11314b0..9b74ff0 100644
--- a/server/routes/auth.js
+++ b/server/routes/auth.js
@@ -297,6 +297,22 @@ router.get('/staff-preview', async (req, res) => {
   return res.redirect(previewUrl)
 })
 
+// Selbstheilung: Portal-Session lebt oft laenger als das preview_session-Cookie
+// (bzw. das Cookie fehlt nach WebView-/Browser-Datenverlust). Ohne gueltiges
+// Preview-Cookie laufen die *.project.webklar.com-Hosts in eine 302-Schleife.
+// Deshalb stellt /me das Preview-Cookie automatisch neu aus, solange die
+// Portal-Session gueltig ist.
+async function refreshPreviewCookie(req, res, payload) {
+  try {
+    const existing = req.cookies?.[PREVIEW_COOKIE_NAME]
+    if (existing && (await verifyPreviewSessionToken(existing))) return
+    const token = await createPreviewSessionToken(payload)
+    res.cookie(PREVIEW_COOKIE_NAME, token, previewSessionCookieOptions())
+  } catch (err) {
+    console.warn('[auth] preview-cookie refresh failed:', err.message)
+  }
+}
+
 router.get('/me', async (req, res) => {
   const raw = req.signedCookies?.[config.cookieName]
   if (!raw) {
@@ -313,6 +329,15 @@ router.get('/me', async (req, res) => {
         const doc = await getDocument(config.collections.customers, session.customerId).catch(() => null)
         if (doc) customer = sanitizeCustomer(doc)
       }
+      await refreshPreviewCookie(req, res, {
+        userId: session.appwriteUserId,
+        customerId: '',
+        email: session.adminEmail || session.email || '',
+        name: session.adminName || session.name || 'Admin',
+        role: 'admin',
+        labels: ['admin'],
+        authSource: 'kundenbereich-admin',
+      })
       return res.json({
         authenticated: true,
         role: 'admin',
@@ -348,6 +373,16 @@ router.get('/me', async (req, res) => {
       customer = await syncCustomerAppwriteUserId(customer, session.appwriteUserId)
     }
 
+    await refreshPreviewCookie(req, res, {
+      userId: session.appwriteUserId,
+      customerId: customer.$id,
+      email: customer.email || session.email || '',
+      name: customer.name || session.name || '',
+      role: 'customer',
+      labels: [],
+      authSource: 'kundenbereich',
+    })
+
     return res.json({
       authenticated: true,
       role: 'customer',