Literally that easy

Author: ArtOfCode-

app/controllers/admin_controller.rb

@@ -65,7 +65,7 @@ def send_all_email
 
     Thread.new do
       emails = User.where.not(confirmed_at: nil).where('email NOT LIKE ?', '%localhost').select(:email).map(&:email)
-      emails.each_slice(50) do |slice|
+      emails.each_slice(49) do |slice|
         AdminMailer.with(body_markdown: params[:body_markdown],
                          subject: params[:subject],
                          emails: slice, community: community)