I once had an issue with a client where every time they launched Outlook 2016, it would error out on the part where you “log on to the mail server and send a test email” saying something about connectivity to the server. This is after signing in on the pop up that verifies your server and everything.
We knew the account wasn’t the issue because we could add it on one of our lab machines.
We knew it wasn’t a DNS issue because we could ping autdiscover.ourdomainname.com.
We knew it wasn’t account credentials because we could sign into Outlook online (OWA).
- Run – regedit. Navigate to: HKEY_CURRENT_USER\Software\Microsoft\Office\x.0\Outlook\AutoDiscover (create if not there)
NOTE: x.0 in the above registry path corresponds to the Outlook version (16.0 = Outlook 2016, 15.0 = Outlook 2013, 14.0 = Outlook 2010, 12.0 = Outlook 2007
- Add the following keys:
Type=DWORD32, Name=ExcludeHttpsRootDomain, Value=1
Type=DWORD32, Name=ExcludeScpLookup, Value=1
Either close out of all windows or reboot. NOTE: I had originally done this on a test user account and had to re-create the keys on the problem user account. Pay attention to which hive you are in (obvious HKLM wouldn’t have this problem).
Try again, should work this time.