Solved (Technics)
I won't know the answer. It's working now ! I guess it was a host issue, very strange. Maybe the mail server blocked it and then unblocked it when I logged a ticket... Everything is possible.
In any case, thanks so much for having taken the time to answer, it was no lost time as I was able to progress on the issue and next time I know what to do.
Tschüss from Brussels
Jean-Michel