Microsoft recently updated the Outlook.com service to improve the service. As part of this they sent out message to those people connecting with Outlook 2013 or Outlook 2016 to alert them to the need to remove and re-add their account in order to continue using the service.
In most cases Outlook should configure the account using no more than the email address and password. However if you are using a custom domain this may not work.
Previously it was possible to connect using Exchange ActiveSync but this isn’t possible any more. If the account setup fails to work automatically it may be because you don’t have auto discover set up for you domain.
Provided you have access to change you DNS this is easy to fix by adding a CNAME with the following values:
- Host Name: autodiscover
- Type: CNAME
- Address: autodiscover.outlook.com
Once that is done you should be able to add your account to Outlook and let the automatic set up sort itself out.
If you have older versions of Outlook it might be a bit more complicated.