Headache ! ticket no updated when using outlook

[gallica]

Afterhaving spend too much time, we need help from the community.
Our problem. using client email program does not update the ticket.
Let me say.
Client open ticket with kayako. OK
Staff response. Ok
Client response using outlook or else : the ticket is not updated. Then when using kayako interface to update the ticket. it's ok.

So what are we missing ? 3 email queues denifed with pop3. Smtp server with CPU Server Settings is OK.

Thanks for you help.