diff --git a/app/controllers/repp/v1/base_controller.rb b/app/controllers/repp/v1/base_controller.rb
index 84d45ea687..ed4ca96523 100644
--- a/app/controllers/repp/v1/base_controller.rb
+++ b/app/controllers/repp/v1/base_controller.rb
@@ -107,7 +107,7 @@ def authenticate_user
       end
 
       def authentication_failure_message
-        if @current_user&.active? && !@current_user.identity_verified?
+        if @current_user&.active? && @current_user.subject.present? && !@current_user.identity_verified?
           I18n.t('registrar.authorization.identity_not_verified')
         else
           I18n.t('registrar.authorization.invalid_authorization_information')
diff --git a/app/models/api_user.rb b/app/models/api_user.rb
index 28561c72ae..3142303c0d 100644
--- a/app/models/api_user.rb
+++ b/app/models/api_user.rb
@@ -39,7 +39,7 @@ def self.min_password_length # Must precede .validates
   after_commit :notify_registrar_subject_changed, on: :update
 
   scope :eligible_for_sign_in, lambda {
-    where(active: true).where.not(verified_at: nil)
+    where(active: true).where('subject IS NULL OR subject = ? OR verified_at IS NOT NULL', '')
   }
 
   def identity_verified?
@@ -47,7 +47,7 @@ def identity_verified?
   end
 
   def eligible_for_sign_in?
-    active? && identity_verified?
+    active? && (subject.blank? || identity_verified?)
   end
 
   def verification_pending?
diff --git a/test/integration/repp/v1/registrar/auth/check_info_test.rb b/test/integration/repp/v1/registrar/auth/check_info_test.rb
index 770174231d..b0678a30e7 100644
--- a/test/integration/repp/v1/registrar/auth/check_info_test.rb
+++ b/test/integration/repp/v1/registrar/auth/check_info_test.rb
@@ -39,8 +39,8 @@ def test_invalid_user_login
     assert_equal json[:message], 'Invalid authorization information'
   end
 
-  def test_rejects_unverified_user_login_with_valid_password
-    @user.update_columns(verified_at: nil)
+  def test_rejects_unverified_user_login_with_valid_password_when_subject_present
+    @user.update_columns(subject: 'EE1234', verified_at: nil)
 
     get '/repp/v1/registrar/auth', headers: @auth_headers
     json = JSON.parse(response.body, symbolize_names: true)
@@ -50,6 +50,16 @@ def test_rejects_unverified_user_login_with_valid_password
     assert_equal false, json[:data][:eligible_for_sign_in]
   end
 
+  def test_allows_unverified_user_login_without_subject
+    @user.update_columns(subject: nil, verified_at: nil)
+
+    get '/repp/v1/registrar/auth', headers: @auth_headers
+    json = JSON.parse(response.body, symbolize_names: true)
+
+    assert_response :ok
+    assert_equal json[:data][:username], @user.username
+  end
+
   def test_returns_error_response_if_throttled
     ENV['shunter_default_threshold'] = '1'
     ENV['shunter_enabled'] = 'true'
diff --git a/test/models/api_user_test.rb b/test/models/api_user_test.rb
index a424debec5..2d9334ab12 100644
--- a/test/models/api_user_test.rb
+++ b/test/models/api_user_test.rb
@@ -159,7 +159,7 @@ def test_linked_with_by_subject_only
     assert_not @user.linked_with?(nil)
   end
 
-  def test_eligible_for_sign_in_requires_active_and_verified
+  def test_eligible_for_sign_in_requires_active_and_verified_when_subject_present
     @user.update_columns(active: true, verified_at: Time.zone.now)
     assert @user.eligible_for_sign_in?
 
@@ -170,6 +170,11 @@ def test_eligible_for_sign_in_requires_active_and_verified
     assert_not @user.eligible_for_sign_in?
   end
 
+  def test_eligible_for_sign_in_allows_unverified_user_without_subject
+    @user.update_columns(active: true, subject: nil, verified_at: nil)
+    assert @user.eligible_for_sign_in?
+  end
+
   def test_subject_change_clears_verification_status_when_subject_previously_present
     @user.update_columns(
       subject: 'EE1234',