Any suggestions

Hello everyone, I’m encountering an issue where Thunderbird is unable to save emails to the Sent Items folder on my IMAP server unless I disable the mail shield feature. The emails send without any problems; the issue only arises when trying to save them to the Sent folder. This is happening on a Windows 10 desktop, and I’m using the latest version of the free antivirus software. I’ve attempted to resolve the problem by whitelisting all the relevant URLs, but this hasn’t helped. However, everything works perfectly when I turn off the mail shield. Any suggestions or fixes would be greatly appreciated. Thank you!