diff --git a/apps/desktop/src/main.tsx b/apps/desktop/src/main.tsx
index 2ed2854..e152423 100644
--- a/apps/desktop/src/main.tsx
+++ b/apps/desktop/src/main.tsx
@@ -444,20 +444,20 @@ function App() {
       if (!res.ok) {
         // Fallback para o handshake por redirecionamento
         const persona = (config?.accessRole ?? accessRole) === "manager" ? "manager" : "collaborator"
-        const redirectTarget = persona === "manager" ? "/dashboard" : "/portal"
+        const redirectTarget = persona === "manager" ? "/dashboard" : "/portal/debug"
         const url = `${resolvedAppUrl}/machines/handshake?token=${encodeURIComponent(token)}&redirect=${encodeURIComponent(redirectTarget)}`
         window.location.href = url
         return
       }
     } catch {
       const persona = (config?.accessRole ?? accessRole) === "manager" ? "manager" : "collaborator"
-      const redirectTarget = persona === "manager" ? "/dashboard" : "/portal"
+      const redirectTarget = persona === "manager" ? "/dashboard" : "/portal/debug"
       const url = `${resolvedAppUrl}/machines/handshake?token=${encodeURIComponent(token)}&redirect=${encodeURIComponent(redirectTarget)}`
       window.location.href = url
       return
     }
     const persona = (config?.accessRole ?? accessRole) === "manager" ? "manager" : "collaborator"
-    const redirectTarget = persona === "manager" ? "/dashboard" : "/portal"
+    const redirectTarget = persona === "manager" ? "/dashboard" : "/portal/debug"
     window.location.href = `${resolvedAppUrl}${redirectTarget}`
   }, [token, config?.accessRole, accessRole, resolvedAppUrl, apiBaseUrl])
 
diff --git a/src/app/portal/debug/page.tsx b/src/app/portal/debug/page.tsx
new file mode 100644
index 0000000..8525691
--- /dev/null
+++ b/src/app/portal/debug/page.tsx
@@ -0,0 +1,65 @@
+"use client"
+
+import { useEffect, useState } from "react"
+
+type Json = Record<string, unknown> | null
+
+export default function PortalDebugPage() {
+  const [authSession, setAuthSession] = useState<Json>(null)
+  const [authStatus, setAuthStatus] = useState<number | null>(null)
+  const [machine, setMachine] = useState<Json>(null)
+  const [machineStatus, setMachineStatus] = useState<number | null>(null)
+  const [error, setError] = useState<string | null>(null)
+
+  useEffect(() => {
+    let cancelled = false
+    ;(async () => {
+      try {
+        const a = await fetch("/api/auth/get-session", { credentials: "include" })
+        const aBody = await a.json().catch(() => null)
+        if (!cancelled) {
+          setAuthStatus(a.status)
+          setAuthSession(aBody as Json)
+        }
+
+        const m = await fetch("/api/machines/session", { credentials: "include" })
+        const mBody = await m.json().catch(() => null)
+        if (!cancelled) {
+          setMachineStatus(m.status)
+          setMachine(mBody as Json)
+        }
+      } catch (err) {
+        if (!cancelled) setError(err instanceof Error ? err.message : String(err))
+      }
+    })()
+    return () => { cancelled = true }
+  }, [])
+
+  return (
+    <div className="mx-auto max-w-3xl space-y-4 p-6">
+      <h1 className="text-lg font-semibold">Diagnóstico de sessão</h1>
+      <p className="text-sm text-neutral-600">Esta página consulta a API com os mesmos cookies desta aba.</p>
+
+      {error ? (
+        <div className="rounded-md border border-rose-200 bg-rose-50 p-3 text-sm text-rose-700">{error}</div>
+      ) : null}
+
+      <section className="rounded-md border border-slate-200 bg-white p-4">
+        <h2 className="mb-2 text-sm font-semibold">/api/auth/get-session</h2>
+        <div className="mb-2 text-xs text-neutral-500">status: {authStatus ?? "—"}</div>
+        <pre className="overflow-x-auto rounded-md bg-slate-50 p-3 text-xs leading-tight">{JSON.stringify(authSession, null, 2)}</pre>
+      </section>
+
+      <section className="rounded-md border border-slate-200 bg-white p-4">
+        <h2 className="mb-2 text-sm font-semibold">/api/machines/session</h2>
+        <div className="mb-2 text-xs text-neutral-500">status: {machineStatus ?? "—"}</div>
+        <pre className="overflow-x-auto rounded-md bg-slate-50 p-3 text-xs leading-tight">{JSON.stringify(machine, null, 2)}</pre>
+      </section>
+
+      <div className="text-xs text-neutral-500">
+        Se algum status for 401/403, os cookies de sessão não estão válidos. Reabra o agente e tente novamente.
+      </div>
+    </div>
+  )
+}
+