If you use Office 365 and encounter an issues using your Hosted Exchange mailbox where Outlook tries to connect to your Outlook.com account by default instead of the mailbox @your-domain-name try making the following changes on your PC.
Step x - Update Your Registry
1. Click Start > Run > Type "regedit" (without quotes) to open the Registry.
2. Locate and then select the following registry subkey: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover
3. Add a DWORD Entry ExcludeExplicitO365Endpoint
4. Value 1
5. Click on the "RedirectServers" folder below the "AutoDiscover" folder and remove any entries that reference Office365, hotmail, LiveMail...etc.
6. Close Registry.
7. Open "Credential Manager" in Windows and remove any logins that reference Office365, Live Mail...etc.
8. From the "Start" menu in Windows, click on the "Settings" gear and go to "Apps & Features", click on Default Apps link and make sure Outlook is selected for default Email app.
9. Then start up Outlook, type in your Email address, and click the "Manual Configure" under the Email address and click Connect.
10. Select "Exchange" icon.
11. Type in your Hosted Exchange Email password.
12. A small pop up box will come up saying that Outlook is trying to connect to "exchange.infoquest.com", click the box "Don't ask about this again" and click the "Allow" button.
13. You might be asked to type in your exchange email password again, then it will set up your account in Outlook.