Symptoms
- Mail autodiscover does not work.
- Microsoft Outlook for Office 365 or Outlook 2019 or later is used as a mail client.
Cause
Microsoft Outlook for Office 365 and Outlook 2019 and later use Microsoft proxy servers for autodiscover requests. The used servers do not support mail servers other than Microsoft Exchange.
Resolution
As a workaround, settings can be configured manually according to the instruction.