Issue Plesk/Dovecot inbox wont update past 9/05

[christoginger]

HI Guys,

Trying to help out a friend and I dont have much experience with dovecot/plesk. BUt my problem is
one of his mailboxes out of quite a few is having an issue where the mail wont update past the 9/05/18. If he accesses the inbox through webmail it all shows ok.

i have tried deleteing the account on thunderbird and recreating - it downloads everything up to that date.
strangely sent items show mail sent using the webmail client - so that is updating.

I have tried a doveadm force-resync on the mailbox but it hasnt fixed it.

Can anyone help?

thanks

Christo