Windows 10 Mail AppAccording to our investigation (12.8.2015), the Mail App of Windows 10 cannot be used as Mail client for the TUHH.
Unfortunately, we did not find any way to configure the mail address!!!
but even if you found the hidden scroll bar in the "Add account" dialog (it will only appear after you moved the mouse pointer into the dialog.) and scrolled down below the "Other Account" button to "Advanced setup", and choose "Internet Account", there seems to be no way to configure an email address! Or where would you enter "firstname.lastname@example.org"?
With these settings you are able to read your imap Mailbox, but sending Mails fails because it uses "xyab1234" as the "mail from" value in the SMTP Dialog.
sendmail: STARTTLS=server, relay=xx.yy.tu-harburg.de [134.28.xx.yy], version=TLSv1/SSLv3, verify=NO, cipher=AES256-SHA, bits=256/256 sendmail: AUTH=server, relay=xx.yy.tu-harburg.de [134.28.xx.yy], authid=xyab1234, mech=PLAIN, bits=0 sendmail: t7EBt59X003056: ruleset=check_mail, arg1=<xyab1234>, relay=xx.yy.tu-harburg.de [134.28.xx.yy], reject=553 5.5.4 <xyab1234>>... Domain name required for sender address xyab1234