diff --git a/app/controllers/api/v1/dossiers_controller.rb b/app/controllers/api/v1/dossiers_controller.rb
index 980ba7e81..9a990734d 100644
--- a/app/controllers/api/v1/dossiers_controller.rb
+++ b/app/controllers/api/v1/dossiers_controller.rb
@@ -2,6 +2,7 @@ class API::V1::DossiersController < APIController
   before_action :fetch_procedure_and_check_token
 
   DEFAULT_PAGE_SIZE = 100
+  MAX_PAGE_SIZE = 1000
   ORDER_DIRECTIONS = { 'asc' => :asc, 'desc' => :desc }
 
   def index
@@ -33,7 +34,12 @@ class API::V1::DossiersController < APIController
   end
 
   def per_page # inherited value from will_paginate
-    [params[:resultats_par_page]&.to_i || DEFAULT_PAGE_SIZE, 1000].min
+    resultats_par_page = params[:resultats_par_page]&.to_i
+    if resultats_par_page && resultats_par_page > 0
+      [resultats_par_page, MAX_PAGE_SIZE].min
+    else
+      DEFAULT_PAGE_SIZE
+    end
   end
 
   def fetch_procedure_and_check_token
diff --git a/app/controllers/users/dossiers_controller.rb b/app/controllers/users/dossiers_controller.rb
index 23cb10410..8c0ccad0f 100644
--- a/app/controllers/users/dossiers_controller.rb
+++ b/app/controllers/users/dossiers_controller.rb
@@ -48,8 +48,11 @@ module Users
     end
 
     def attestation
-      if dossier.attestation.pdf.attached?
+      if dossier.attestation&.pdf&.attached?
         redirect_to url_for(dossier.attestation.pdf)
+      else
+        flash.notice = "L'attestation n'est plus disponible sur ce dossier."
+        redirect_to dossier_path(dossier)
       end
     end
 
diff --git a/app/models/dynamic_smtp_settings_interceptor.rb b/app/models/dynamic_smtp_settings_interceptor.rb
new file mode 100644
index 000000000..885c4b8e9
--- /dev/null
+++ b/app/models/dynamic_smtp_settings_interceptor.rb
@@ -0,0 +1,16 @@
+class DynamicSmtpSettingsInterceptor
+  def self.delivering_email(message)
+    if ENV['SENDINBLUE_BALANCING'] == 'enabled'
+      if rand(0..99) < ENV['SENDINBLUE_BALANCING_VALUE'].to_i
+        message.delivery_method.settings = {
+          user_name: ENV['SENDINBLUE_USER_NAME'],
+          password: ENV['SENDINBLUE_SMTP_KEY'],
+          address: 'smtp-relay.sendinblue.com',
+          domain: 'smtp-relay.sendinblue.com',
+          port: '587',
+          authentication: :cram_md5
+        }
+      end
+    end
+  end
+end
diff --git a/app/models/procedure.rb b/app/models/procedure.rb
index 6a6d3ecd6..96a427dbb 100644
--- a/app/models/procedure.rb
+++ b/app/models/procedure.rb
@@ -595,14 +595,18 @@ class Procedure < ApplicationRecord
 
   def move_type_de_champ_attributes(types_de_champ, type_de_champ, new_index)
     old_index = types_de_champ.index(type_de_champ)
-    types_de_champ.insert(new_index, types_de_champ.delete_at(old_index))
-      .map.with_index do |type_de_champ, index|
-        {
-          id: type_de_champ.id,
-          libelle: type_de_champ.libelle,
-          order_place: index
-        }
-      end
+    if types_de_champ.delete_at(old_index)
+      types_de_champ.insert(new_index, type_de_champ)
+        .map.with_index do |type_de_champ, index|
+          {
+            id: type_de_champ.id,
+            libelle: type_de_champ.libelle,
+            order_place: index
+          }
+        end
+    else
+      []
+    end
   end
 
   def before_publish
diff --git a/app/models/types_de_champ/linked_drop_down_list_type_de_champ.rb b/app/models/types_de_champ/linked_drop_down_list_type_de_champ.rb
index 71f0784b1..24410c6f6 100644
--- a/app/models/types_de_champ/linked_drop_down_list_type_de_champ.rb
+++ b/app/models/types_de_champ/linked_drop_down_list_type_de_champ.rb
@@ -53,7 +53,7 @@ class TypesDeChamp::LinkedDropDownListTypeDeChamp < TypesDeChamp::TypeDeChampBas
 
   def check_presence_of_primary_options
     if !PRIMARY_PATTERN.match?(drop_down_list.options.second)
-      errors.add(libelle, "doit commencer par une entrée de menu primaire de la forme <code style='white-space: pre-wrap;'>--texte--</code>")
+      errors.add(libelle.presence || "La liste", "doit commencer par une entrée de menu primaire de la forme <code style='white-space: pre-wrap;'>--texte--</code>")
     end
   end
 
diff --git a/app/views/champs/repetition/_show.html.haml b/app/views/champs/repetition/_show.html.haml
index 508593712..8b3240829 100644
--- a/app/views/champs/repetition/_show.html.haml
+++ b/app/views/champs/repetition/_show.html.haml
@@ -1,10 +1,11 @@
 - champs = champ.rows.last
-- index = (champ.rows.size - 1) * champs.size
-%div{ class: "row row-#{champs.first.row}" }
-  - champs.each.with_index(index) do |champ, index|
-    = fields_for "#{attribute}[#{index}]", champ do |form|
-      = render partial: "shared/dossiers/editable_champs/editable_champ", locals: { champ: champ, form: form }
-      = form.hidden_field :id
-      = form.hidden_field :_destroy, disabled: true
-  %button.button.danger.remove-row
-    Supprimer
+- if champs.present?
+  - index = (champ.rows.size - 1) * champs.size
+  %div{ class: "row row-#{champs.first.row}" }
+    - champs.each.with_index(index) do |champ, index|
+      = fields_for "#{attribute}[#{index}]", champ do |form|
+        = render partial: "shared/dossiers/editable_champs/editable_champ", locals: { champ: champ, form: form }
+        = form.hidden_field :id
+        = form.hidden_field :_destroy, disabled: true
+    %button.button.danger.remove-row
+      Supprimer
diff --git a/config/env.example b/config/env.example
index 4f704adab..c3c40d089 100644
--- a/config/env.example
+++ b/config/env.example
@@ -46,8 +46,14 @@ SENTRY_DSN_JS=""
 MATOMO_ENABLED="disabled"
 MATOMO_ID="73"
 
-SENDINBLUE_ENABLED="disabled"
+SENDINBLUE_BALANCING=""
+SENDINBLUE_BALANCING_VALUE=""
+SENDINBLUE_ENABLED=""
 SENDINBLUE_CLIENT_KEY=""
+SENDINBLUE_SMTP_KEY=""
+SENDINBLUE_USER_NAME=""
+
+
 CRISP_ENABLED="disabled"
 CRISP_CLIENT_KEY=""
 
diff --git a/config/environments/development.rb b/config/environments/development.rb
index 385185b36..718db3436 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -45,14 +45,26 @@ Rails.application.configure do
   config.assets.raise_runtime_errors = true
 
   # Action Mailer settings
-  config.action_mailer.delivery_method = :letter_opener_web
-  # Configure default root URL for generating URLs to routes
-  config.action_mailer.default_url_options = {
-    host: 'localhost',
-    port: 3000
-  }
-  # Configure default root URL for email assets
-  config.action_mailer.asset_host = "http://" + ENV['APP_HOST']
+
+  if ENV['SENDINBLUE_ENABLED'] == 'enabled'
+    config.action_mailer.delivery_method = :smtp
+    config.action_mailer.smtp_settings = {
+      user_name: Rails.application.secrets.sendinblue[:username],
+      password: Rails.application.secrets.sendinblue[:smtp_key],
+      address: 'smtp-relay.sendinblue.com',
+      domain: 'smtp-relay.sendinblue.com',
+      port: '587',
+      authentication: :cram_md5
+    }
+  else
+    config.action_mailer.delivery_method = :letter_opener_web
+    config.action_mailer.default_url_options = {
+      host: 'localhost',
+      port: 3000
+    }
+
+    config.action_mailer.asset_host = "http://" + ENV['APP_HOST']
+  end
 
   Rails.application.routes.default_url_options = {
     host: 'localhost',
diff --git a/config/environments/production.rb b/config/environments/production.rb
index 8837fb88b..262c15c4b 100644
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@@ -77,6 +77,16 @@ Rails.application.configure do
       port: '2525',
       authentication: :cram_md5
     }
+  elsif ENV['SENDINBLUE_ENABLED'] == 'enabled'
+    config.action_mailer.delivery_method = :smtp
+    config.action_mailer.smtp_settings = {
+      user_name: Rails.application.secrets.sendinblue[:username],
+      password: Rails.application.secrets.sendinblue[:smtp_key],
+      address: 'smtp-relay.sendinblue.com',
+      domain: 'smtp-relay.sendinblue.com',
+      port: '587',
+      authentication: :cram_md5
+    }
   else
     config.action_mailer.delivery_method = :mailjet
   end
diff --git a/config/initializers/dynamic_smtp_settings_interceptor.rb b/config/initializers/dynamic_smtp_settings_interceptor.rb
new file mode 100644
index 000000000..a3f8e2d13
--- /dev/null
+++ b/config/initializers/dynamic_smtp_settings_interceptor.rb
@@ -0,0 +1 @@
+ActionMailer::Base.register_interceptor "DynamicSmtpSettingsInterceptor"
diff --git a/config/secrets.yml b/config/secrets.yml
index 7ad675ffe..2ac8aa244 100644
--- a/config/secrets.yml
+++ b/config/secrets.yml
@@ -54,7 +54,9 @@ defaults: &defaults
     webhook_secret: <%= ENV['HELPSCOUT_WEBHOOK_SECRET'] %>
   sendinblue:
     enabled: <%= ENV['SENDINBLUE_ENABLED'] == 'enabled' %>
+    username: <%= ENV['SENDINBLUE_USER_NAME'] %>
     client_key: <%= ENV['SENDINBLUE_CLIENT_KEY'] %>
+    smtp_key: <%= ENV['SENDINBLUE_SMTP_KEY'] %>
     api_v3_key: <%= ENV['SENDINBLUE_API_V3_KEY'] %>
   matomo:
     enabled: <%= ENV['MATOMO_ENABLED'] == 'enabled' %>
diff --git a/spec/models/type_de_champ_shared_example.rb b/spec/models/type_de_champ_shared_example.rb
index d0b6e4ecf..a710b4ef0 100644
--- a/spec/models/type_de_champ_shared_example.rb
+++ b/spec/models/type_de_champ_shared_example.rb
@@ -148,4 +148,22 @@ shared_examples 'type_de_champ_spec' do
       expect(cloned_procedure.types_de_champ.first.types_de_champ).not_to be_empty
     end
   end
+
+  describe "linked_drop_down_list" do
+    let(:type_de_champ) { create(:type_de_champ_linked_drop_down_list) }
+
+    it 'should validate without label' do
+      type_de_champ.drop_down_list_value = 'toto'
+      expect(type_de_champ.validate).to be_falsey
+      messages = type_de_champ.errors.full_messages
+      expect(messages.size).to eq(1)
+      expect(messages.first.starts_with?("#{type_de_champ.libelle} doit commencer par")).to be_truthy
+
+      type_de_champ.libelle = ''
+      expect(type_de_champ.validate).to be_falsey
+      messages = type_de_champ.errors.full_messages
+      expect(messages.size).to eq(2)
+      expect(messages.last.starts_with?("La liste doit commencer par")).to be_truthy
+    end
+  end
 end