Have a look at this Technote. It's a bit dated, but it is still useful for identifying some things to check. Hopefully it will get you on the right path. Since the software and presumably the server are all the same, should be a configuration somewhere on your client.

Thank you for the hint, unfortunately it doesn't fix the issue.

This problem is driving me crazy ! I really dont' know what is "off" on my client.

You'll probably want to contact your help desk team for some assistance reviewing the logs. I would guess there is something in the way of an error there that would point to the problem. Issues like this can have many causes, so it's best to start with the logs and go from there.