Rescue Notify badrequest errors (#1828)

app/mailers/devise_notify_mailer.rb

@@ -5,14 +5,18 @@ class DeviseNotifyMailer < Devise::Mailer
     @notify_client ||= ::Notifications::Client.new(ENV["GOVUK_NOTIFY_API_KEY"])
   end
 
-  def send_email(email, template_id, personalisation)
-    return true if intercept_send?(email)
+  def send_email(email_address, template_id, personalisation)
+    return true if intercept_send?(email_address)
 
     notify_client.send_email(
-      email_address: email,
+      email_address:,
       template_id:,
       personalisation:,
     )
+  rescue Notifications::Client::BadRequestError => e
+    Sentry.capture_exception(e)
+
+    true
   end
 
   def personalisation(record, token, url, username: false)

spec/mailers/devise_notify_mailer_spec.rb

@@ -8,6 +8,11 @@ RSpec.describe DeviseNotifyMailer do
     let(:name) { "test" }
     let(:password) { "password" }
     let(:role) { "data_coordinator" }
+    let(:bad_request_error) do
+      # rubocop:disable RSpec/VerifiedDoubles
+      Notifications::Client::BadRequestError.new(double(code: 200, body: ""))
+      # rubocop:enable RSpec/VerifiedDoubles
+    end
 
     before do
       allow(described_class).to receive(:new).and_return(devise_notify_mailer)
@@ -39,6 +44,21 @@ RSpec.describe DeviseNotifyMailer do
           User.create!(name:, organisation:, email:, password:, role:)
         end
       end
+
+      context "when notify mailer raises BadRequestError" do
+        before do
+          allow(notify_client).to receive(:send_email).and_raise(bad_request_error)
+        end
+
+        let(:domain) { Rails.application.credentials[:email_allowlist].first }
+        let(:email) { "test@#{domain}" }
+
+        it "does not raise an error" do
+          expect {
+            User.create!(name:, organisation:, email:, password:, role:)
+          }.not_to raise_error
+        end
+      end
     end
 
     context "when the rails environment is not staging" do