Some guests can't login to my Team - something to do with their organisation settings?

[Liz Pommer]

Ok, not sure how to solve this one...

I have Teams set up with my O365 licence, into which I have invited many guests. 

However, guests from one particular organisation can't log in. The IT team from that org has started a trial rollout of O365 with a few people (not mine) and are suggesting that they've blocked access to the people I want to invite into my Team.

How does that work - can't I just invite anyone, from anywhere? How does another org stop their staff from accessing my Team? 

I need to be able to advise my potential guests how to validate their invitation and get into my Team - do they take different steps and can an org really block staff from logging into another domain's Team? 

[#2]

If they’ve set up a tenant with that domain name you’re inviting them with they need to be synced up to that tenant otherwise you have to invite them with another email address!
Ask the IT admin‘s of their environment to synchronize them to their office 365 AAD

This is all becauseif their domain a society associated with the tenant in office 365 this will be used to authenticate the users if they’re not synchronized/ created, this will fail

[#3 · Accepted solution]

If their IT doens't have them licensed for Teams then they won't be able to join as a guest to other Teams as it requires a home tenant Teams login to join as guest to other orgs. It's rather annoying but it's how it's designed especially when you try to invite someone with hosted 365 and Teams is disabled.

Your best alternative would be to get personal addresses from these folks and invite them via their personal addresses, tell them use incognito when accepting the invite and sign in with a Microsoft account (or create one, or use gmail) when accepting and then they can login with this account to access your Teams.

Ideally their IT Team should allow them to use Teams otherwise it's just going to make their lives miserable when they do enable it later and they have to either switch or be invited again later with their org account.

Althou Teams will support multiple login's at some point it may not be an issue if that released by the time they get access to Teams in their org.....

Anyway, good luck.

[#4]

Yeah! If my scenario isn’t the case, aka they are synced to office 365 , Chris suggestion is probably the cause

[#5]

@Liz Pommer We have been able to work around this limitation using deep links in the target tenant hosting the Teams environment.  Find the team the user has access to and choose "Get link to Team" from the ellipses menu.  Have the user visit that link in a private browsing session and they should be able to authenticate using their home org account into your Teams environment.

[#6]

Thanks @Chris Webb and all, I'm going with this response as best for two reasons: 

1.  The solution has to be super-simple as the people I'm inviting in as guests are not going to know how to do things such as private browsing (busy execs, not tech-savvy in any way)
2. I've used the option of inviting a different email address before and it works very well and I think it will be the simplest solution this time around. It works well because you can log in with whichever email suits at the time and you can still see all docs and conversations. I can invite anyone, anytime - don't try to stop me hahaha. 

I think the complication with this one is that the proposed Guests are using an on-premise email, and although the transition to O365 has not started for them, there is a new O365 licence in their name but is not yet activated (?) or something like that. And their IT is working with Microsoft to make sure it's very tightly controlled in these early stages. I don't want to, nor can I, interfere with that.

So, if I need to deliver my project and I'm going to use Teams to do it, I'm going to find a way to make this work - so, thanks for the reminder about inviting them via a private email address!! It's a bit like the time my sister and cousin wanted to block their teenage daughters from setting up Facebook accounts - they both went to a friend's house and did it on the sly. You can't stop people inventing ways to make things work for them so you need to work together to maintain the best level of transparency and control. But, it's not my place to tell this to the IT Director of a large organisation for whom I don't work :) 

[#7]

I'll definitely keep this one up my sleeve for next time... Thanks!