Confirmation mails sent to subscribers end up in the promotions tab

Whenever a visitor subscribes to my newsletter the corresponding confirmation mail gets sent to the promotions tab of the user and hence is very often overlooked. As such most of my subscribers remain unconfirmed. I tried changing the sending email id as well as the text of the mail but the issue persists. How to get the mail’s delivered to the main inbox.

P.S. I am using mailpoet sending service not external.