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Hello!
I was in a middle of a migration from Exchange 2010 to 2019 (passing between to 2016 first), and we are doing a laboratory stage. We are having issues trying to connect Outlook 2013/2016 to Exchange 2010, only if it is running on Windows 10, because we have tested it on Windows 7 and runs without any issue.
The issue is that when I want to configure for first time the Outlook profile for a test user, the configuration wizard reports the error "Exchange Server connection is not available. Outlook has to be online..." or something like that. And I repeat, same Outlook version on Windows 7 configures, opens and can be use it, without any issue.
Does anybody know what is going on? I have tested it with Outlook 2013 and 2016.
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Hi anonymous user
Have you enabled TLS 1.2 on Exchange 2010?
If haven't yet you may follow the guide in the following links:
Exchange Server TLS guidance, part 1: Getting Ready for TLS 1.2
Exchange Server TLS guidance Part 2: Enabling TLS 1.2 and Identifying Clients Not Using It
Exchange Server TLS guidance Part 3: Turning Off TLS 1.0/1.1
Thanks for your reply.
But I have found the solution.
The key was Outlook Connection Optimisation feature. This feature seems to Outlook expect that default gateway exists and responds. In my testing stage I had configured a false gateway. In the following article talks about it, and shows how to disable this feature configuring the registry. In my case I decided to not disabled it because I am cloning the same configuretion of the production stage, so what I has done is to configure to every machine with a IP address of one of the machine as default gateway in the testing stage, for oulook clients can reach a device that responds. I already tested it and works as a charm.
https://blog.rmilne.ca/2014/03/27/outlook-unable-to-connect-to-exchange-default-gateway-not-found/
Hi anonymous user
Thanks for the update and glad to hear the issue has been resolved!
I've also seen this issue before: Outlook and default gateway
Glad you figured it out.
Due to a recent update in forum policy, the question author is not able to accept their own answers.
I have written a brief summary of this issue.
Please feel free to accept it as the answer to the question to help other community members.
Thanks again for the sharing!
Issue Symptom:
Unable to connect Outlook to Exchange mailboxes when the default gateway on the device is invaild
Solution: