VSTS will no longer allow creation of new MSA users with custom domain names backed by AzureAD
On September 15, 2016, the Azure Active Directory (Azure AD) team blocked the ability to create new Microsoft accounts using email addresses in domains that are configured in Azure AD. Many VSTS customers expressed concern when this change happened. As a result, we worked with the Azure AD team to get a temporary exception for our service to be excluded from this limitation. Over the past year, we have improved our experience for connecting accounts to Azure AD and we are now ready to end this exception. This means that, as of March 30th, 2018, a new user in your organization will not be able to create a new MSA sign-in with a custom domain name if that domain name is already used by an Azure AD tenant. This may affect the way you bring new users into your VSTS account, so we wanted to give you advance warning of the change as well as give you guidance on how to move forward.
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