Can't connect Outlook 2016 to my O365 Mailbox



  • I have an Office 365 account with the email
  • I have an old MSA account with the email
  • Windows 10 - Creators Update (but tried this with a fully patched version immediately before updating to Creators Update
  • Outlook 2016 latest (installed from Office 365

In the past, I had no problem with this.


I login to Windows 10 with my MSA account. Within Windows 10 => Settings => Accounts, I see my MSA account listed as "Outlook" and can firm it's using a Hotmail server to sync.


When I try to add another account in Windows 10 for Exchange using the same email, it tells me that email is already in use.


When I try to add my Office 365 account to Outlook, it constantly rejects the credentials I enter. Instead, it re-prompts me to enter the credentials... except it autofills my email as "MicrosoftAccount\".


No matter if I use my Office 365 (Azure AD) password with what's provided or if I remove "MicrosoftAccount\" from the email address, Outlook refuses to connect to it.


The behavior is that because I'm using the same email, Outlook now assumes it's an MSA account and refuses to use the domain with the autodiscovery DNS entry for my domain to resolve to O365 Exchange servers to lookup the account.


The result: I can't use Outlook 2016 for my Office 365 email.


This was not the case in the past. I rebuilt the same machine in September 2016 and had no problem with this same setup. So something changed in Windows 10 / Outlook 2016 to impact this. 

23 Replies

Probably something new with the Creators update. I havent updated to it yet, so I cannot test to see if I can reproduce. In any case, I'd advise removing the alias from your MSA, there are all kinds of other issues you will run into. Microsoft has finally decided to pull the plug on this type of configuration, in case you missed it:

No... I tried this same setup prior to updating to the Creators Update as I said at the start of the post.

While I know and agree the setup I have is no longer allowed, it is still supported and I have never had an issue with it. Until it's required you move away from it, I'm not removing the alias as I have a ton of things that use that MSA account. I'm not removing it to fix this one issue that I expect will create countless others.... not all groups @ Microsoft are ready to deal with that.

Try changing the autofilled email from "MicrosoftAccount\" to "\" and see if that works.

Unfortunately not... I did try that when it first happened.

I had the same problem. It is due to having the same username for O365 and MSA.

My advice is to change the username for the MSA: I have had no problems anymore.

It is actually very simple: see

Hope it helps...

Just not worth renaming IMHO with so many places where I use this that are clearly based on the signin email and not the MSA account ID.

Switching to a different MSA is safer. Annoying... worked just fine a few months ago. Lovely UX yet again Redmond... so glad my primary machine is MacOS.

Andrew, I think instead that it is very well worth.

Here is why:

  • Where the MSA account ID is involved (as in the Windows login and everything about the MSA itself) all continues to work as usual: you don't need to change anything.
  • Ditto for every other place where you could have used the emai as signinl, because you still have the email address itself (in O365) and therefore all continues to work as usual.

Try it.

Just my two cents...

I think you missed my point... I get what you're saying & completely agree.

But for the sites that use signin email for the identifier and not (like they should), the MSA account ID, changing your email screws you over as suddenly your account is orphaned on that site.

I've done this before with other MSA's and I've seen that happen. I've used this MSA for 10yrs+, and I'm not sure where it would be an issue... so I'm not about to be the one to test it until MSFT forces this change.

I had the same problem.
I my case it seemed to be related to two-factor auth being enabled in O365.

Fixed it by temporarily (only while setting up the account in OL2016) disabling 2FA.

How long did you have to wait for the disable of MFA to take place?  

As far as I remember disabling/enabling was effective immediately.

I will confirm that it was 2fa that was blocking my sign in also, once I disabled it, it went through first time although still took about 3 minutes to set up the account.

HI Mr.Andrew Connell
i had face the same issue and i have overcome with the solution.
Issue cause : Due to improper SSL certificate communication within the PC & exchange.

The simplest way to resolve this issue is to just download and install Microsoft Support and Recovery Assistant for Office 365 (; "this tool is diagnostic tool for Microsoft Products" Once done with installing the tool go through the tool and select the outlook and describe the your problem then tool will rectify's the issue. then you can configure the outlook reliably.

Thanks & best regards
Ravi Kiran
Thanks that useful
Thanks for that link! This worked perfectly as well! I have no idea why just trying to add a profile would not work, but utility did the trick! I'll be keeping that link in the bag of tricks for other clients that I migrate to O365.
Glad, to here the news! :)
Glad, this post was helpful to you:)
haha, Great work it would be useful in future case.