Outlook 2016 taking an extremely long time for the autodiscover to detect the account settings,
Outlook 2016 for Windows will attempt to resolve https://autodiscover.yourdomain.com/autodiscover/autodiscover.xml 11 times with a 30 second+ wait time between each attempt before discovering the CNAME record configured on your domain, which points to autodiscoverredirect.yourdomain.com. This causes the initial autodiscover process to take 20-30 minutes.
Unlike previous versions of Outlook, Outlook 2016 does not allow manual configuration of server settings, and is instead solely dependent on the autodiscover process.
There are two workarounds available:
1. Wait 20-30 minutes for the autodiscover process to complete.
2. Add the below registry key, The below registry settings will force Outlook to go directly to the HTTP redirection method and allow the account to be setup nearly instantly.