How to set up an incoming email server for an user in Odoo?

openerp,imap,odoo,odoo-8,fetchmail

Finally, I've found the problem, which is very specific I guess, but who knows, may be this answer helps someone in the future. I've realized that the module fetchmail_attach_from_folder was installed in all the computers which were giving errors, on the contrary, it was not installed in those which there...