While sending singles emails, the messages get routed via SMTP and the POP3 server of your email recipient before landing into the inbox. However, when you send emails in bulk, covering the journey from sent to received isn't easy. The emails server comes with certain limitations on the number of emails sent in a day or hour. Furthermore, the bigger the campaign, the lower rate of delivery may get. Ergo, the selection of the right smtp server for bulk email becomes critical for the success of your email marketing campaign.