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Poor Implementation of Azure B2B Collaboration
Yammer fans (Yammistas?) were very excited when Microsoft announced the general availability for Azure B2B Collaboration (guest user access) for Yammer native mode networks on March 22. The Tech Community blog post was preceded by message center notification MC244062 on March 11 (roadmap item 80993). It’s another step along the path of bringing Yammer more into the Microsoft 365 ecosystem by supporting a feature that other apps have had for several years.
Limited Guest Support for Now
The announcement says that guest access in Yammer is “powered by Azure B2B” and that “Azure B2B collaboration enables you to share your company’s applications and services with guest users from any other organization.” The disconnect between the two statements is the glaring fact that Yammer doesn’t support guest access for anyone except people with Azure AD accounts in other Office 365 tenants. This is very different to Microsoft 365 Groups, Teams, and Planner, all of which support guest members with Microsoft Service Accounts (MSAs) and accounts in other directories, like Gmail.
The limitation existed when I tested the feature while it was in preview. I expected it to be a short-term issue while Microsoft sorted out authentication for external access to Yammer. At the time, I could add external users from outside Office 365 to a Yammer community, but all attempts to connect were rebuffed (Figure 1).

Eventually, the penny dropped, and I found documentation covering features still in progress, including support for:
Personal email, non-Microsoft 365 business email, and phone number-based legacy accounts – Users with Microsoft 365 Business email accounts can be added as guests. Other email domains like Gmail or Yahoo mail etc. will not be supported in this release.
This is the only place in the Microsoft pages which discuss guest access for Yammer which makes the limited support clear. Many potential external people are excluded from Yammer-based collaboration until Microsoft upgrades support for guest users to put it on par with the other Microsoft 365 apps.
Struggling with Guest Accounts
It’s been a few months since I tested guest access in Yammer. When I tried to use the guest account from other Office 365 tenant I previously used for testing, I encountered some problems, and the account never managed to connect.
I removed and added the account back into a Yammer community to no avail. To get a clean start, I removed the guest account from Azure AD and recreated it from scratch. The recreated account works perfectly with Teams and SharePoint Online, but cannot join a Yammer community. I reported the problem to Microsoft and was told that some fixes rolling out should help. It didn’t, and I was never able to resolve the problem, even after removing and recreating the guest account several times.
Geography Blues
I then tried to add an account from another Office 365 tenant, only to be told that “cross-geography guests are not supported” (Figure 2). Checking the network settings confirmed that the Yammer network for my European tenant is in the U.S. while the test tenant I tried to use is in the European Union.

The documentation says, “Today we enable organizations to host Yammer in two data centers – Europe and North America. With this new guest support, users will be able to add guests from their same geography.” Yammer is the only Microsoft 365 application which imposes this restriction.
Native Mode Only
The other big thing to remember is that guest access is only possible for Yammer networks in native mode for Microsoft 365. In this mode, Yammer communities use Microsoft 365 Groups for membership and identity management and capture compliance records for messages. All new enterprise Yammer networks operate in this mode, but many older networks, including those run by Microsoft, use the older “non-native” mode, and don’t use Azure B2B collaboration to support external users. A process is available to switch older networks into native mode.
Frustrating and Unusable
After struggling with Yammer’s fragile support for Azure B2B Collaboration for several weeks and despite the best efforts of the Yammer engineers to find out why things didn’t work as they should , my conclusion is that this software is not fit for purpose. Unlike Groups, Teams, SharePoint Online, and Planner, all of which manage to make guest accounts work without too much fuss, Yammer’s implementation has many problems. Microsoft continues to make a big thing of Yammer. Given this fiasco, I can’t understand why.
Update May 6: The Yammer engineers figured out and fixed the underlying problem, so I can add a guest account to a Yammer community now (within the documented limits).
Fully agree with the points raised – however the biggest usecase you left out of this post is actually around enabling cross tenant collaboration if a company for some reason is split into multiple tenants – or as part of M&As as part of the integration offering before consolidating everyone on the same tenant. For this purpose it works reasonably well and it’s serving us well.
Yammer is not really being positioned as a tool for external collaboration with “random people” – but much more an enterprise collaboration tool for “knowledge communities” and informal networks within the company or with close partners
I would probably also add to the “Geography Blues” part that if an EU company wants to move their existing tenant from US->EU geo (gdpr and all..) – the default offering is “delete and start again” – and a recommendation to hire a consultancy firm to build a custom migration using the export API if you want to keep anything from the last 10 years…
Maybe that’s a topic for a different post 🙂
Good points. I hadn’t considered the M&A aspect, but you’re dead right on that point.
It doesn’t either respect the reverse. That is where you have multiple domains in the Same Tenant but need to split them.
There maybe information barriers you need to set up. For instance we have partner accounts that are considered internal by 365 but are for external people. We don’t want those people in our main tenant yammer, but would like to use them in other Yammer scenarios. We cannot do that as Yammer forces them to our home network and they can view our public groups.
Still a very poor implmentation for security and yes I have previously spoken to Microsoft support about it.
Now I know that proper guest access is not working the way I would need it (thanks again Tony). We have hundreds of independent partners who use gmail and the like to work with us. Works perfectly fine in Teams, SharePoint and OneDrive. Appears coming up on a decade since Microsoft bought this product that some of its core tech has still not made the transistion to working the same way as the rest of the suite.