For security reasons, the Light version of OWA (Outlook Web App) has been disabled.
Unfortunately, mailboxes that were already being used in Light mode cannot currently be switched to the normal view. Microsoft is already working on a solution to this problem.
Until an update is available, please use an email client such as Outlook [1] or Thunderbird [2] to access your Exchange mailbox.
Thank you for your understanding.
[1] https://faq.tickets.tu-dresden.de/v/ItemID=23 [2] https://faq.tickets.tu-dresden.de/v/ItemID=603