Outlook 2016 IMAP trouble

[G]

Hello List,

I'm facing an issue with dovecot (2.2.27) IMAP  and Outlook as a client. 
I have some users that use
Outlook (2016) as  a client . One of them has a desktop PC in the office 
and a laptop machine
which I've setup some days ago . The user did some work, during the 
weekend, in his laptop
(filling messages into IMAP folders) and to his (and mine) surprise, 
today in the office he saw that none of his
work is reflected on the server. Messages are not where they supposed to 
be .Tomorrow he will bring the laptop
over to check, but I have seen this problem again in the past  again 
with outlook 2016 as a client
(specifically I've had a user which during work he was deleting or 
renaming folders which appear fine
on his copy of outlook (ost) but not on the server). Anyone has any 
experience with dovecot and outlook
and related problems ?


thanks in advance
George