After updating macOS from 10.12.4 to 10.12.5, Outlook 2016 stopped connecting to our Exchange 2010 SP3 server.

Existing identities show a yellow light in the account settings.

Starting with a fresh install of macOS 10.12.5 does the same thing.

Outlook 2016 is updated to the latest version.

The only message we get while trying to add an account is "Unable to connect to the server. Please try again."

The only thing we found that works is backing everything up and reinstall 10.12.4...

What changed? How can we fix this?

  • It would appear that version 15.35 is still having the same issue. Freshly downloaded and installed this morning. All details for Exchange connection appear to be correct. However just says server is unavailable. *edit - not sure why this has been voted down. Surely the information is relevant!?
    – Luke
    Jul 3, 2017 at 11:16

1 Answer 1


I am having the same issue - called Microsoft and they said it is a known issue with the latest 1701 builds of Outlook at this time. They are working on a patch but in the interim the only suggestion is to install an older copy.

The version that does appear to work is v15.30 of build 1701.

The last two versions of that build - v15.33 and v15.34 have the same issue.

  • Is there a way to download this version?
    – Pat Betts
    Jun 1, 2017 at 18:12
  • Found it! support.office.com/en-us/article/… Will try to install v15.30 and report back.
    – Pat Betts
    Jun 1, 2017 at 18:18
  • Well that does not work. We just reinstalled a clean macos 10.12.5 with version Office 2016 v15.30.0 (17010700) and we still can't connect to our Exchange server.
    – Pat Betts
    Jun 2, 2017 at 13:40

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