diff --git a/templates/confirmation/link_expired.html b/templates/confirmation/link_expired.html
index 0f84c0f272..81a9c3038b 100644
--- a/templates/confirmation/link_expired.html
+++ b/templates/confirmation/link_expired.html
@@ -4,12 +4,10 @@
 
 <div class="pitch">
     <hr/>
-    <p class="lead">Whoops. The confirmation link has expired.</p>
+    <p class="lead">Whoops. The confirmation link has expired or been deactivated.</p>
 
     <p>
-        If you're not sure how to generate a new one, shoot us a line at
-        <a href="mailto:{{ support_email }}">{{ support_email }}</a>
-        and we'll get this resolved shortly.
+        Please contact your organization administrator for a new one.
     </p>
 
 </div>
diff --git a/zerver/tests/test_auth_backends.py b/zerver/tests/test_auth_backends.py
index 21861dc944..e41ec23480 100644
--- a/zerver/tests/test_auth_backends.py
+++ b/zerver/tests/test_auth_backends.py
@@ -540,7 +540,7 @@ class GitHubAuthBackendTest(ZulipTestCase):
 
     def test_github_backend_new_user(self) -> None:
         rf = RequestFactory()
-        request = rf.get('/complete')
+        request = rf.get('/complete', HTTP_HOST=self.user_profile.realm.host)
         request.session = {}
         request.user = self.user_profile
         self.backend.strategy.request = request
diff --git a/zerver/tests/test_email_change.py b/zerver/tests/test_email_change.py
index 127855ea67..f8fe532a2f 100644
--- a/zerver/tests/test_email_change.py
+++ b/zerver/tests/test_email_change.py
@@ -52,7 +52,7 @@ class EmailChangeTestCase(ZulipTestCase):
                                     type=Confirmation.EMAIL_CHANGE)
         url = confirmation_url(key, user_profile.realm.host, Confirmation.EMAIL_CHANGE)
         response = self.client_get(url)
-        self.assert_in_success_response(["Whoops. The confirmation link has expired."], response)
+        self.assert_in_success_response(["The confirmation link has expired or been deactivated."], response)
 
     def test_confirm_email_change(self) -> None:
         user_profile = self.example_user('hamlet')
diff --git a/zerver/tests/test_signup.py b/zerver/tests/test_signup.py
index ff84c97bc0..8b02e618ed 100644
--- a/zerver/tests/test_signup.py
+++ b/zerver/tests/test_signup.py
@@ -1040,7 +1040,7 @@ class MultiuseInviteTest(ZulipTestCase):
         result = self.client_post(invite_link, {'email': email})
 
         self.assertEqual(result.status_code, 200)
-        self.assert_in_response("Whoops. The confirmation link has expired.", result)
+        self.assert_in_response("The confirmation link has expired or been deactivated.", result)
 
     def test_invalid_multiuse_link(self) -> None:
         email = self.nonreg_email('newuser')
@@ -1707,6 +1707,26 @@ class UserSignUpTest(ZulipTestCase):
              'from_confirmation': '1'},  subdomain="zephyr")
         self.assert_in_success_response(["We couldn't find your confirmation link"], result)
 
+    def test_failed_signup_due_to_empty_realm_in_prereg_user(self) -> None:
+        """
+        Largely to test a transitional state, where we started requiring the
+        realm in PreregistrationUser (if realm_creation is False), and wanted
+        to make sure we had properly disabled any existing confirmation links that
+        didn't have the realm set.
+        """
+        email = "newuser@zulip.com"
+        password = "password"
+        self.client_post('/accounts/home/', {'email': email})
+        PreregistrationUser.objects.update(realm=None)
+        result = self.client_post(
+            '/accounts/register/',
+            {'password': password,
+             'key': find_key_by_email(email),
+             'terms': True,
+             'full_name': "New User",
+             'from_confirmation': '1'})
+        self.assert_in_success_response(["The confirmation link has expired or been deactivated."], result)
+
     def test_failed_signup_due_to_restricted_domain(self) -> None:
         realm = get_realm('zulip')
         realm.invite_required = False
diff --git a/zerver/views/registration.py b/zerver/views/registration.py
index 8e9935f136..787e4e4952 100644
--- a/zerver/views/registration.py
+++ b/zerver/views/registration.py
@@ -64,7 +64,9 @@ def accounts_register(request):
         realm = None
     else:
         realm = get_realm(get_subdomain(request))
-        if prereg_user.realm is not None and prereg_user.realm != realm:
+        if prereg_user.realm is None:
+            return render(request, 'confirmation/link_expired.html')
+        if prereg_user.realm != realm:
             return render(request, 'confirmation/link_does_not_exist.html')
 
     if realm and not email_allowed_for_realm(email, realm):