Guest user access to Group conversations


Since a guest user cannot access Office 365 Group conversations, i thought I'd give it a shot and try to access the data through the Office 365 Groups API


As expected, got a Unauthroized exception to read/created a new conversation. Is there a way external users can participate in the conversations ? Ready to build a custom UI for this if the data can be fetched through APIs !


Also, when Owner of a group created a new conversation in the Office 365 Group, the external guest user did not receive the email. So how can the guest user participate in the conversation.

7 Replies
best response confirmed by Juan Carlos González Martín (MVP)

Guest members of Office 365 Groups cannot directly access Group conversations because they cannot access EOL resources without a license.

Nevertheless, they can participate in conversations by email, meaning that they should receive an email for every post and they can post by email.

If this does not happen, see

Salvatore is correct!

Hi there,


I am the engineer manager responsible for Guest Access in O365 Groups. We are working with several partner teams on enabling guest access to O365 Group conversations via REST APIs (Microsoft Graph). We hope to bring it online first quarter 2018.


We are also planning guest access via Outlook clients (mobile, web, etc.) but we still on early stages and don't have timeline to share.





Fantastic ! Thanks for your response...Really looking forward to have conversations for guest in Graph API in early 2018 !

What about guest access to Group calendars?  Can that be done?

Thanks for the info, Salvatore! That is very unfortunate as that gaping design flaw makes the conversations feature near worthless. If you have any external users, why not just scrap teams and use regular old email?  I hope they either fix this flaw soon or my clients and company switch over to Slack.

Hi Dan, Teams now fully support guest users, therefore overcoming Outlook Group conversation shortcomings. See

So, no need to switch to Slack. ;)