I have had this annoying issue with Office 365 Groups (Groups, not Teams). In our IT team we have several Office 365 Groups. Some users do see these groups in Outlook 2016 almost immediately, other users do not see anything (I’m in this group). When I select Browse Office 365 Groups in Outlook, I see an error message saying We can’t show you group right now. Make sure Outlook is connected and try again as shown in the following screenshot:

In Office 365 Teams there are the HiddenFromExchangeClients and HiddenFromAddressListsEnabled properties (see the Hiding Office 365 Groups Created by Teams from Exchange Clients article from Tony Redmond for more information) , but this is only Office 365 Groups and not an Office 365 Team. And both properties are set to FALSE, so this is not the case.

I am using Office 365 ProPlus Click-to-Run which checks Exchange Online first for Autodiscover purposes, but then I realized I had been experimenting with some registry keys to change Autodiscover behavior. When checking the registry, I found the ExcludeExplicitO365Endpoint DWORD set to 1 as shown in the following screenshot:

So, Autodiscover checks on-premises Exchange server and is redirected to Office 365 for Exchange Online information. Unfortunately, this does not retrieve any information regarding Office 365 groups. After changing this value to ‘0’, Autodiscover starts with Office 365 and does retrieve the correct Office 365 Groups information.

Related to this, there are also scenarios where Outlook does not detect Office 365 groups using Autodiscover where the (primary) SMTP address of the Office 365 group is not correct. For example, where the SMTP address of the group is (for example) IT-Calendar@contoso.com. You can change the primary address of the group using the following command in Exchange Online PowerShell:

Set-UnifiedGroup Alias -PrimarySmtpAddress IT-Calendar@contoso.mail.onmicrosoft.com

Or when you want to add the SMTP address as a secondary address:

Set-UnifiedGroup IT-Calendar -EmailAddresses @{add="it-calendar@contoso.mail.onmicrosoft.com"}

This should also solve the problem.