Improve error message when does not match in completed form

app/controllers/send_submission_email_controller.rb

@@ -10,16 +10,17 @@ class SendSubmissionEmailController < ApplicationController
   SEND_DURATION = 30.minutes
 
   def create
-    @submitter =
-      if params[:template_slug]
-        Submitter.joins(submission: :template).find_by!(email: params[:email].to_s.downcase,
-                                                        template: { slug: params[:template_slug] })
-      elsif params[:submission_slug]
-        Submitter.joins(:submission).find_by!(email: params[:email].to_s.downcase,
-                                              submission: { slug: params[:submission_slug] })
-      else
-        Submitter.find_by!(slug: params[:submitter_slug])
-      end
+    if params[:template_slug]
+      @submitter = Submitter.joins(submission: :template).find_by!(email: params[:email].to_s.downcase,
+                                                                   template: { slug: params[:template_slug] })
+    elsif params[:submission_slug]
+      @submitter = Submitter.joins(:submission).find_by(email: params[:email].to_s.downcase,
+                                                        submission: { slug: params[:submission_slug] })
+
+      return redirect_to submissions_preview_completed_path(params[:submission_slug], status: :error) unless @submitter
+    else
+      @submitter = Submitter.find_by!(slug: params[:submitter_slug])
+    end
 
     RateLimit.call("send-email-#{@submitter.id}", limit: 2, ttl: 5.minutes)
 

app/controllers/submissions_preview_controller.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 class SubmissionsPreviewController < ApplicationController
+  around_action :with_browser_locale
   skip_before_action :authenticate_user!
   skip_authorization_check
 

app/views/submissions_preview/completed.html.erb

@@ -28,6 +28,11 @@
           <%= f.hidden_field :submission_slug, value: @submission.slug %>
           <%= f.label :email, t('email'), class: 'label' %>
           <%= f.email_field :email, value: current_user&.email || params[:email], required: true, class: 'base-input', placeholder: t('send_copy_to_email') %>
+          <% if params[:status] == 'error' %>
+            <span class="label-text-alt text-red-400 mt-1">
+              <%= t('please_enter_your_email_address_associated_with_the_completed_submission') %>
+            </span>
+          <% end %>
         </div>
         <toggle-submit dir="auto" class="form-control">
           <%= f.button button_title(title: t('send_copy_to_email'), disabled_with: t('starting')), class: 'base-button' %>