External Access - lookup not working

Iron Contributor
Hi there,
we are just helping a customer of us to get started with Teams. Unfortunately the Teams users are not able to contact external recipients. So if you are typing john.taylor@contoso.com the addition search externally is not shown. For sure we have checked the basic policies like meeting and messaging policies as well as the external access.
 
Background:
The company utilized Skype for Business some few days ago. Their Edge server was faulty and their assistance in this case was not good, so we could not fix it. Due to COVID-19 they decided that they need Teams quickly. We removed the S4B farm in a clean and calm manner. Removed the users from S4B server to free up the SIP addresses, removed further components like mediation server and so on until we could removed the central management store and executed the last steps. Even the RTC attributes are now removed from the forest.
Then we removed the internal and external DNS records. Following we have set the four needed DNS entries for Teams / S4B Online.
 
I have seen a post where it it was said, that you need the S4B license. Is that true?
 
So afterwards we mentioned interesting symptoms. We created a cloud only user who could be found from external, but he cannot find other external users. Hybrid identity users (former S4B OnPrem users) cannot be found and they cannot find external users.
 
The Teams Upgrade to TeamsOnly has been finished.
 
Anybody an idea?

Kind regards,
Christian
 
3 Replies

Hi,

I assume you have verified that external sharing is properly set up at the tenant level (not only Teams). This happened to a customer of mine and the problem was that external sharing was disabled at the tenant level.

@Juan Carlos González Martín 

I will check this again. But to be exactly... like usual for Microsoft there are round about 5 locations for external sharing. Which settings would be the relevant ones?

Try following these steps. It helped us resolve a similar issue we had at the beginning of our teams rollout.

https://docs.microsoft.com/en-us/microsoftteams/guest-access-checklist