Hi, 

Special Characters in email subjects ie '&' or '@' or emoji's

We have an issue that whenever certain special characters ie, '&' or '@' or emoji's are used within the subject line of an email and sent to our users we find the user IMAP configured email clients hit an IMAP error and are unable to send / receive / sync mailboxes from the server. 

(SmarterMail Enterprise Build 6996 (Feb 26, 2019))

This has been noted across Windows live mail 2012, Outlook 2013 and Outlook 2016. We have ruled out Anitvirus integrations.

Which ever mailbox we move the offending email to within the email account fails to sync, ie. if we move from inbox to deleted items, deleted items will then fail to sync. to resolve the email has to be completely removed via logging into the users webmail account and deleting from there.