Good afternoon, for about a month and a half, every time I send a campaign, a high percentage of emails bounce. These emails have the following pattern in their content:
"This is an automatically generated Delivery Status Notification.
Unable to deliver message to the following recipients, due to being unable to connect successfully to the destination mail server."
At the end of the bounce email, an email address comes what makes each email different.
What is the reason a high percentage of emails are bouncing and all with the same pattern? Is it a matter of the SMTP server configuration that I am using or is it a phplist configuration where I have to make some adjustments?