em client no server connection with windows 8 to arcor

windows 8 and em client: Hello, I tried to get connection from em client to my mails at www.arcor.de on a windows 8 based computer. It failed because of “no server connection” failure. Then I tried the same on a windows xp based pc. When installing the mail address manually, in contrast to windows 8 there popped up two questions if authentifications should be sent to the mailservers of arcor which are required. Then the installation was successful. Why don’t appear the authentific questions in windows 8? Besides, to repair the problem in windows 8 was not successful, too. Thank you.

send us your IMAP logs please - it will tell us more.