Why do letters not reach recipients with smtp authentication?

Question

Yii

Good afternoon,
There is a site on yii1 , lying on a virtual hosting. To perform smtp authentication on the server, I use the YiiMailer component, the component is connected and working.
Letters are sent only to mailboxes that are entered in the domain zone ( [email protected] ) , and letters are not sent to all other addresses such as [email protected] . What could be the reason?