Windows Essentials Mail password problem.

cannot change password in Windows Essentials Mail application. When I open the mail program a box opens (it has the old password ) I type the new password in the box a tick remember and all new e-mails are downloaded. But the next time the program is opened the old password is there and the new password must be typed in. have opened settings, options ect to the enter and remember new password parts but the old password remains (Have checked with password sniffer) ran Essentials repair but it did not fix problem.