diff --git a/lib/outreach/discover.ts b/lib/outreach/discover.ts
index 86f30cf5..73a0baad 100644
--- a/lib/outreach/discover.ts
+++ b/lib/outreach/discover.ts
@@ -21,6 +21,7 @@ import { searchSerp, hasValueSerpKey } from "@/lib/alerts/valueserp";
 import { isThirdPartyHost } from "@/lib/leadCampaign";
 import { businessSearch } from "./freeSearch";
 import { normalizeHost } from "./cold";
+import { looksLikeLoginWall } from "./loginWall";
 
 export type DiscoveredProspect = {
   host: string;
@@ -178,7 +179,10 @@ function looksBlocked(status: number): boolean {
 
 async function fetchHtml(
   url: string,
-): Promise<{ ok: true; html: string } | { ok: false; error: string; status?: number }> {
+): Promise<
+  | { ok: true; html: string; finalUrl: string }
+  | { ok: false; error: string; status?: number; loginRequired?: boolean }
+> {
   try {
     const res = await fetch(url, {
       headers: { "user-agent": SEED_UA },
@@ -186,7 +190,15 @@ async function fetchHtml(
       redirect: "follow",
     });
     if (!res.ok) return { ok: false, status: res.status, error: `HTTP ${res.status}` };
-    return { ok: true, html: await res.text() };
+    const html = await res.text();
+    // The redirect onto a login page is visible here even though the login
+    // form itself may only exist after scripts run, so this catches the wall
+    // without paying for a render.
+    const wall = looksLikeLoginWall({ requestedUrl: url, finalUrl: res.url, html });
+    if (wall.loginRequired) {
+      return { ok: false, loginRequired: true, error: `the site requires a login — ${wall.reason}` };
+    }
+    return { ok: true, html, finalUrl: res.url };
   } catch (err) {
     return { ok: false, error: err instanceof Error ? err.message : "unknown" };
   }
@@ -204,8 +216,12 @@ async function fetchHtml(
 async function loadSeedHtml(
   url: string,
   allowRender: boolean,
-): Promise<{ html: string; rendered: boolean } | { error: string }> {
+): Promise<{ html: string; rendered: boolean } | { error: string; loginRequired?: boolean }> {
   const direct = await fetchHtml(url);
+  // A login wall is settled: rendering it again only renders the login page.
+  if (!direct.ok && direct.loginRequired) {
+    return { error: direct.error, loginRequired: true };
+  }
   if (direct.ok) {
     const hasCandidates = extractOutboundProspects({ html: direct.html, sourceUrl: url, limit: 1 }).length > 0;
     if (hasCandidates || !allowRender) return { html: direct.html, rendered: false };
@@ -216,6 +232,7 @@ async function loadSeedHtml(
   const { renderPage } = await import("./render");
   const rendered = await renderPage(url);
   if (rendered.ok) return { html: rendered.html, rendered: true };
+  if (rendered.loginRequired) return { error: rendered.error, loginRequired: true };
 
   // Prefer the render error: when both fail it is the more specific of the
   // two, and it distinguishes a bot challenge from an ordinary failure.
@@ -242,14 +259,24 @@ export async function discoverFromSeed(input: {
    * businesses. Keeps ordinary directories at one cheap page load.
    */
   detailHopThreshold?: number;
-}): Promise<{ prospects: DiscoveredProspect[]; error?: string; notes?: string[] }> {
+}): Promise<{
+  prospects: DiscoveredProspect[];
+  error?: string;
+  notes?: string[];
+  /** Set when the seed was withheld pending a login, so the UI can offer to store one. */
+  loginRequired?: boolean;
+}> {
   const limit = input.limit ?? 100;
   const allowRender = input.render !== false;
   const notes: string[] = [];
 
   const seed = await loadSeedHtml(input.seedUrl, allowRender);
   if ("error" in seed) {
-    return { prospects: [], error: `seed ${input.seedUrl} failed: ${seed.error}` };
+    return {
+      prospects: [],
+      error: `seed ${input.seedUrl} failed: ${seed.error}`,
+      loginRequired: seed.loginRequired,
+    };
   }
   if (seed.rendered) notes.push(`rendered ${input.seedUrl} in a browser`);
 
@@ -371,10 +398,17 @@ export async function discoverProspects(input: {
   seedUrls?: string[];
   limit?: number;
   source?: SearchSource;
-}): Promise<{ prospects: DiscoveredProspect[]; serpCalls: number; errors: string[] }> {
+}): Promise<{
+  prospects: DiscoveredProspect[];
+  serpCalls: number;
+  errors: string[];
+  /** Seeds that returned a login wall — the UI offers to store credentials for these. */
+  loginRequiredSeeds: string[];
+}> {
   const limit = input.limit ?? 50;
   const merged = new Map<string, DiscoveredProspect>();
   const errors: string[] = [];
+  const loginRequiredSeeds: string[] = [];
   let serpCalls = 0;
 
   const queries = (input.queries ?? []).slice(0, 5);
@@ -396,8 +430,9 @@ export async function discoverProspects(input: {
     // most often paste in.
     const res = await discoverFromSeed({ seedUrl, limit, depth: 2 });
     if (res.error) errors.push(res.error);
+    if (res.loginRequired) loginRequiredSeeds.push(seedUrl);
     for (const p of res.prospects) if (!merged.has(p.host)) merged.set(p.host, p);
   }
 
-  return { prospects: [...merged.values()].slice(0, limit), serpCalls, errors };
+  return { prospects: [...merged.values()].slice(0, limit), serpCalls, errors, loginRequiredSeeds };
 }
diff --git a/lib/outreach/loginWall.ts b/lib/outreach/loginWall.ts
new file mode 100644
index 00000000..075b29cb
--- /dev/null
+++ b/lib/outreach/loginWall.ts
@@ -0,0 +1,107 @@
+// Tell a login wall apart from an empty directory.
+//
+// Both look identical to seed discovery: HTTP 200, a page, and no business
+// links on it. Reporting "no businesses found" for a site that simply wanted
+// a login sends the user off to debug their search terms when the actual
+// problem is that they were never shown the page.
+//
+// Instagram is the motivating case and a good illustration of why status
+// codes are useless here — asking for a search page returns 200, having
+// quietly redirected to /accounts/login/?next=<the page you asked for>.
+//
+// Kept dependency-free so both the fetch path and the render path can use it:
+// a redirect is visible to plain fetch, while a password field on a
+// JS-rendered login screen only appears once scripts have run.
+
+/** Paths a site sends you to when it wants credentials. */
+const LOGIN_PATH_RE =
+  /(^|\/)(accounts\/login|login|log-in|signin|sign-in|sign_in|auth\/login|users\/sign_in|session\/new|checkpoint)(\/|$|\?)/i;
+
+/**
+ * Query parameters a login page uses to remember where you were going.
+ * Their presence alongside a login path is what distinguishes "you were
+ * bounced here" from "you asked for the login page".
+ */
+const RETURN_PARAM_RE = /[?&](next|return_to|returnurl|redirect(_uri|_to)?|continue|dest|destination)=/i;
+
+const PASSWORD_INPUT_RE = /<input[^>]+type=["']password["']/i;
+
+/** Phrases that accompany a credential form rather than ordinary page copy. */
+const LOGIN_COPY_RE =
+  /(forgot (your )?password|log in to continue|sign in to continue|please log in|login required|create an account to)/i;
+
+export type LoginWallVerdict = {
+  loginRequired: boolean;
+  /** Why we think so — surfaced to the user so the call is auditable. */
+  reason: string | null;
+};
+
+/**
+ * Decide whether `html` (fetched from `finalUrl`, having been asked for
+ * `requestedUrl`) is a login wall.
+ *
+ * The strongest signal is a redirect off the requested page onto a login
+ * path, because that is the site explicitly refusing the request. A password
+ * field is next: ordinary directory pages don't carry one. Login copy alone
+ * is not enough — plenty of real pages have a "log in" link in the header —
+ * so it only counts as corroboration for a page that also moved us.
+ */
+export function looksLikeLoginWall(input: {
+  requestedUrl: string;
+  finalUrl?: string;
+  html?: string;
+}): LoginWallVerdict {
+  const requested = safeUrl(input.requestedUrl);
+  const final = safeUrl(input.finalUrl ?? input.requestedUrl);
+
+  const movedUs =
+    Boolean(final && requested) &&
+    (final!.pathname !== requested!.pathname || final!.host !== requested!.host);
+
+  const finalIsLoginPath = final ? LOGIN_PATH_RE.test(final.pathname) : false;
+  const carriesReturn = final ? RETURN_PARAM_RE.test(final.search) : false;
+
+  // Redirected onto a login path: unambiguous.
+  if (movedUs && finalIsLoginPath) {
+    return {
+      loginRequired: true,
+      reason: carriesReturn
+        ? `redirected to ${final!.pathname} carrying the page you asked for as a return parameter`
+        : `redirected to ${final!.pathname}`,
+    };
+  }
+
+  const html = input.html ?? "";
+  const hasPasswordField = PASSWORD_INPUT_RE.test(html);
+
+  // A password field on the page we were served, when we asked for something
+  // that was not a login page.
+  if (hasPasswordField && !(requested && LOGIN_PATH_RE.test(requested.pathname))) {
+    return {
+      loginRequired: true,
+      reason: movedUs
+        ? `served a password field after redirecting to ${final?.pathname ?? "another page"}`
+        : "the page contains a password field",
+    };
+  }
+
+  // Moved us somewhere that reads like a login screen without matching a
+  // known login path — covers hosts with unusual routes.
+  if (movedUs && LOGIN_COPY_RE.test(html)) {
+    return {
+      loginRequired: true,
+      reason: `redirected to ${final?.pathname ?? "another page"}, which reads like a sign-in screen`,
+    };
+  }
+
+  return { loginRequired: false, reason: null };
+}
+
+function safeUrl(value: string | undefined): URL | null {
+  if (!value) return null;
+  try {
+    return new URL(value);
+  } catch {
+    return null;
+  }
+}
diff --git a/lib/outreach/render.ts b/lib/outreach/render.ts
index 9999991e..4ba6fc8a 100644
--- a/lib/outreach/render.ts
+++ b/lib/outreach/render.ts
@@ -25,6 +25,7 @@
 
 import type { Browser, BrowserContext } from "playwright";
 import { isPrivateAddress } from "./mailboxDiscovery";
+import { looksLikeLoginWall } from "./loginWall";
 import dns from "node:dns/promises";
 import net from "node:net";
 
@@ -98,7 +99,14 @@ async function hostIsPublic(hostname: string): Promise<boolean> {
 
 export type RenderResult =
   | { ok: true; html: string; status: number; finalUrl: string }
-  | { ok: false; error: string; status?: number; challenged?: boolean };
+  | {
+      ok: false;
+      error: string;
+      status?: number;
+      challenged?: boolean;
+      /** The page was withheld pending a login, not missing. */
+      loginRequired?: boolean;
+    };
 
 /** Page titles a bot-protection interstitial serves instead of the real page. */
 const CHALLENGE_RE = /just a moment|attention required|verifying you are human|checking your browser/i;
@@ -172,10 +180,25 @@ export async function renderPage(url: string): Promise<RenderResult> {
     }
 
     const html = await page.content();
+    const finalUrl = page.url();
+
+    // A login wall answers 200 with a real page, so it has to be caught by
+    // what the page is rather than by the status. Reported as a failure
+    // because the caller asked for a directory and did not get one.
+    const wall = looksLikeLoginWall({ requestedUrl: url, finalUrl, html });
+    if (wall.loginRequired) {
+      return {
+        ok: false,
+        status,
+        loginRequired: true,
+        error: `the site requires a login — ${wall.reason}`,
+      };
+    }
+
     return {
       ok: true,
       status,
-      finalUrl: page.url(),
+      finalUrl,
       html: html.length > MAX_HTML_BYTES ? html.slice(0, MAX_HTML_BYTES) : html,
     };
   } catch (error) {
diff --git a/tests/login-wall.test.ts b/tests/login-wall.test.ts
new file mode 100644
index 00000000..1eb4014d
--- /dev/null
+++ b/tests/login-wall.test.ts
@@ -0,0 +1,93 @@
+import { describe, it, expect } from "vitest";
+import { looksLikeLoginWall } from "@/lib/outreach/loginWall";
+
+// The exact redirect Instagram served for a seed search URL: HTTP 200, but
+// bounced onto the login page with the requested URL preserved in ?next=.
+const IG_REQUESTED =
+  "https://www.instagram.com/explore/search/keyword/?q=military%203d%20modeling%20games";
+const IG_FINAL =
+  "https://www.instagram.com/accounts/login/?next=https%3A%2F%2Fwww.instagram.com%2Fexplore%2Fsearch%2Fkeyword%2F%3Fq%3Dmilitary%2B3d%2Bmodeling%2Bgames%26__coig_login%3D1";
+
+describe("looksLikeLoginWall", () => {
+  it("catches the Instagram redirect that reported as 'no businesses found'", () => {
+    const v = looksLikeLoginWall({ requestedUrl: IG_REQUESTED, finalUrl: IG_FINAL });
+    expect(v.loginRequired).toBe(true);
+    expect(v.reason).toMatch(/accounts\/login/);
+    expect(v.reason).toMatch(/return parameter/);
+  });
+
+  it("catches it from the rendered password field alone, without the redirect", () => {
+    const v = looksLikeLoginWall({
+      requestedUrl: IG_REQUESTED,
+      finalUrl: IG_REQUESTED,
+      html: '<form><input name="username"><input type="password" name="pass"></form>',
+    });
+    expect(v.loginRequired).toBe(true);
+    expect(v.reason).toMatch(/password field/);
+  });
+
+  it("recognises other common login routes", () => {
+    for (const path of [
+      "/login",
+      "/signin",
+      "/sign-in",
+      "/users/sign_in",
+      "/session/new",
+      "/auth/login",
+    ]) {
+      const v = looksLikeLoginWall({
+        requestedUrl: "https://dir.test/browse",
+        finalUrl: `https://dir.test${path}?return_to=%2Fbrowse`,
+      });
+      expect(v.loginRequired, path).toBe(true);
+    }
+  });
+
+  it("does not misfire on a directory with a 'Log in' link in the header", () => {
+    const v = looksLikeLoginWall({
+      requestedUrl: "https://dir.test/browse",
+      finalUrl: "https://dir.test/browse",
+      html: '<header><a href="/login">Log in</a></header><ul><li><a href="https://acme.test">Acme</a></li></ul>',
+    });
+    expect(v.loginRequired).toBe(false);
+  });
+
+  it("does not misfire when the user deliberately seeded a login page", () => {
+    const v = looksLikeLoginWall({
+      requestedUrl: "https://dir.test/login",
+      finalUrl: "https://dir.test/login",
+      html: '<input type="password">',
+    });
+    expect(v.loginRequired).toBe(false);
+  });
+
+  it("does not treat an ordinary redirect as a login wall", () => {
+    const v = looksLikeLoginWall({
+      requestedUrl: "https://dir.test/browse",
+      finalUrl: "https://dir.test/browse/page-1",
+      html: "<ul><li><a href='https://acme.test'>Acme</a></li></ul>",
+    });
+    expect(v.loginRequired).toBe(false);
+  });
+
+  it("does not treat a bot challenge as a login wall", () => {
+    const v = looksLikeLoginWall({
+      requestedUrl: "https://cf.test/search",
+      finalUrl: "https://cf.test/search",
+      html: "<title>Just a moment...</title><div id='challenge-running'></div>",
+    });
+    expect(v.loginRequired).toBe(false);
+  });
+
+  it("catches a cross-host SSO bounce", () => {
+    const v = looksLikeLoginWall({
+      requestedUrl: "https://dir.test/browse",
+      finalUrl: "https://accounts.sso.test/signin?continue=https%3A%2F%2Fdir.test%2Fbrowse",
+    });
+    expect(v.loginRequired).toBe(true);
+  });
+
+  it("survives malformed URLs without throwing", () => {
+    expect(looksLikeLoginWall({ requestedUrl: "not a url" }).loginRequired).toBe(false);
+  });
+});