You go to https://<domain.com>/autodiscover/autodiscover.xml is accessible. Some jack-hole web guy set up autodiscover on the website. You can edit the registry to exclude the root domain.
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Outlook\AutoDiscover\
DWORD: ExcludeHttpsRootDomain
Value: 1
The other records you can exclude, also under the Autodiscover key are as follows. Use a value of 1 to enable, delete the key if you no longer want to exclude these checks.
DWORD: ExcludeScpLookup
DWORD: ExcludeHttpsAutoDiscoverDomain
DWORD: ExcludeHttpRedirect //I DON’T EXCLUDE THIS ONE BECAUSE I USE IT
DWORD: ExcludeSrvRecord
To resolve permanently, log into cpanel and change the email routing from Local Mail Exchanger to Remote Mail Exchanger.
