Hey @Kseniya 

Thank you for reaching out to the Klaviyo Community for help with your bounced emails.

There are a few different reasons why an email will soft bounce like your customers inbox is full, they have a vacation notice/auto reply, the server was not able to deliver at the time of send. Unfortunately these are completely out of your control and the best practice is to list clean regularly to minimize how many bounces you see. This is vital to maintain good deliverability with email service providers. If you don’t list clean it can possibly have a negative impact and can increase your bounce rates. Check out these other community post that talk about bounces and deliverability. 

Hope this helps! Thank you again for being a member of the Klaviyo Community!