Connecting to exchange from remote location

Question

We are running exchange 2019 internally at our company. All of the users on the domain have no issues with their email connecting to the server. However, if i try to connect to a mailbox from a PC that is outside of their network, it won't connect. An outlook login prompts me for credentials which i provide and eventually a microsoft sign in pops ups. I plug in my email address and it tells me that the username may be incorrect but it isn't. I went to the microsoft remote connectivity analyzer and it seems to pass with flying colors. Any thoughts would be appreciated.

Answer 1

Hi @itdweeb99

What Outlook version are you using?
If you are using Outlook 2016 version 16.0.6741.2017 or later versions, I suppose the possible cause may be the new Outlook feature to try to connect to O365 first.

Please try adding the following value to the registry on the affected device and see if it can get rid of the problem.
Path: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover
(If the AutoDiscover key doesn't exist, please create it manually)

Add a DWORD value named ExcludeExplicitO365Endpoint and set its value data to 1.

Restart Outlook and see if you can connect without problems.

---

If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.