Seems like VSO team rooms are deprecated. THere are some MS Teams,  though.
Related:
http://www.infoworld.com/article/3154997/application-development/microsoft-closes-the-door-on-visual-studios-team-rooms.html
https://jbs.zendesk.com/agent/tickets/1018773

General Info

Plugin Description

Allows sending notifications from the TeamCity server to Visual Studio Online team rooms.

Plugin Development Status

Experimental. Stable.

Download

The latest successful build is available on the public TeamCity server. Compatible with TeamCity 8.1.x+

Installation

1. Put vso-rooms.zip into the <TeamCity Data Directory>/plugins folder.
2. Restart the server.

The notifier is disabled after the plugin installation. You can enable it on the Administration | VS Online Notifier page.

Configuration

Users are required to enable alternate credentials in their Visual Studio Online account.

To send notification messages, a user account in Teamcity is required. A separate account for notifications is recommended.
The following information needs to be provided on the Notification Rules | VS Online notifier page for the specified user account:

• the Visual Studio Online account
• the target Team Room
• the user's credentials to connect to the room (the alternate credentials specified in Visual Studio Online earlier).

Notifications on a particular event sent by several users to the same room will be merged.

After testing and saving the connection settings, you can configure notification rules defining what to watch an when to send notifications.

When the rule is saved, TeamCity will send notifications to the configured Visual Studio Online Team Room as events happen.

See the related blog-post for step-by-step instructions .

Development Links

The sources and issues on GitHub.
Builds at the JetBrains public TeamCity instance.