diff --git a/app/controllers/concerns/invitation.rb b/app/controllers/concerns/invitation.rb
index 2d1d84c1..33ab51bd 100644
--- a/app/controllers/concerns/invitation.rb
+++ b/app/controllers/concerns/invitation.rb
@@ -7,7 +7,7 @@ module Invitation
 
       emails_array.each do |email|
         new_user = User.find_by(email: email)
-        if new_user.nil?
+        if new_user.nil? || !new_user.opted_out?
           User.invite!({ email: email }, current_user)
           new_user = User.find_by(email: email)
         end
diff --git a/app/views/devise/mailer/invitation_instructions.html.erb b/app/views/devise/mailer/invitation_instructions.html.erb
index 27a1c0c4..3c444218 100644
--- a/app/views/devise/mailer/invitation_instructions.html.erb
+++ b/app/views/devise/mailer/invitation_instructions.html.erb
@@ -9,3 +9,5 @@
 <% end %>
 
 <p><%= t("devise.mailer.invitation_instructions.ignore") %></p>
+<hr>
+<small>Click on <%= link_to "Unsubscribe", mailkick_unsubscribe_url %>, to stop receiving invitation mails.</small>
diff --git a/app/views/devise/mailer/invitation_instructions.text.erb b/app/views/devise/mailer/invitation_instructions.text.erb
index f4912bf4..bdd7599b 100644
--- a/app/views/devise/mailer/invitation_instructions.text.erb
+++ b/app/views/devise/mailer/invitation_instructions.text.erb
@@ -9,3 +9,5 @@
 <% end %>
 
 <%= t("devise.mailer.invitation_instructions.ignore") %>
+
+Click on <%= mailkick_unsubscribe_url %>, to stop receiving invitation mails.