diff --git a/app/controllers/api/v1/registrant/auth_controller.rb b/app/controllers/api/v1/registrant/auth_controller.rb
index 5be48f558..929d5b5c9 100644
--- a/app/controllers/api/v1/registrant/auth_controller.rb
+++ b/app/controllers/api/v1/registrant/auth_controller.rb
@@ -21,7 +21,7 @@ module Api
           if token
             render json: token
           else
-            render json: { error: 'Cannot create generate session token' }
+            render json: { errors: [{ base: ['Cannot create generate session token'] }] }
           end
         end
 
@@ -46,7 +46,7 @@ module Api
           allowed_ips = ENV['registrant_api_auth_allowed_ips'].to_s.split(',').map(&:strip)
           return if allowed_ips.include?(request.ip) || Rails.env.development?
 
-          render json: { errors: ['Not authorized'] }, status: :unauthorized
+          render json: { errors: [{ base: ['Not authorized'] }] }, status: :unauthorized
         end
       end
     end
diff --git a/app/controllers/api/v1/registrant/base_controller.rb b/app/controllers/api/v1/registrant/base_controller.rb
index bc5fa21d7..4df0d226c 100644
--- a/app/controllers/api/v1/registrant/base_controller.rb
+++ b/app/controllers/api/v1/registrant/base_controller.rb
@@ -29,7 +29,7 @@ module Api
           if decryptor.valid?
             sign_in decryptor.user
           else
-            render json: { errors: ['Not authorized'] }, status: :unauthorized
+            render json: { errors: [{base: ['Not authorized']}] }, status: :unauthorized
           end
         end
       end
diff --git a/test/integration/api/registrant/registrant_api_authentication_test.rb b/test/integration/api/registrant/registrant_api_authentication_test.rb
index 14ef1c879..97651b029 100644
--- a/test/integration/api/registrant/registrant_api_authentication_test.rb
+++ b/test/integration/api/registrant/registrant_api_authentication_test.rb
@@ -42,7 +42,7 @@ class RegistrantApiAuthenticationTest < ActionDispatch::IntegrationTest
     assert_equal(401, response.status)
     json_body = JSON.parse(response.body, symbolize_names: true)
 
-    assert_equal({ errors: ['Not authorized'] }, json_body)
+    assert_equal({ errors: [base: ['Not authorized']] }, json_body)
 
     ENV['registrant_api_auth_allowed_ips'] = @original_whitelist_ip
   end
diff --git a/test/integration/api/registrant/registrant_api_domains_test.rb b/test/integration/api/registrant/registrant_api_domains_test.rb
index 3e966b192..1c77131c4 100644
--- a/test/integration/api/registrant/registrant_api_domains_test.rb
+++ b/test/integration/api/registrant/registrant_api_domains_test.rb
@@ -81,7 +81,7 @@ class RegistrantApiDomainsTest < ActionDispatch::IntegrationTest
     assert_equal(401, response.status)
     json_body = JSON.parse(response.body, symbolize_names: true)
 
-    assert_equal({ errors: ['Not authorized'] }, json_body)
+    assert_equal({ errors: [base: ['Not authorized']] }, json_body)
   end
 
   def test_details_returns_401_without_authorization