htaccess and postie ?

Finally I think it is because of a subdomain.
I have https://www.clg.fr a primary domain controller (dummy) and a sub-domain https://www.intra-clg.fr
and subdomain postie does not work.
Any idea?

I think you need to look at your apache logs to see what is happening.
You can also check if postie is working by clicking the run postie debug button.