Where do I add the relevant exclusion? IMAP accounts, Thunderbird error.

[OJK]

I have several email accounts. I use Mozilla Thunderbird as the email client. I connect via IMAP. When moving emails between IMAP accounts Thunderbird reports an error "Connection to server <myservername> timed out" (tends to happen for emails with attachments of over 2MB) . Pausing Kaspersky cures the problem. This issue does not occur when receiving or sending emails, just when I move them between IMAP accounts.

Can anyone advise how I configure Kaspersky to allow me to move the emails between IMAP accounts.