My users are having massive problems inviting their external clients to SharePoint Online Sites. It's very difficult to tell the difference between MS's convoluted processes/systems vs things that are just plain bugs.
Can somebody please clear this question up for me?...
Let's say "our" organization has Office 365 on our domain: ourdomain.com
We've set up a SharePoint Site that we'd like to give external users access to. As it turns out they also happen to use Office 365 on their own company's domain: externaldomain.com
If we invite firstname.lastname@example.org to one of our SharePoint Sites...
a) Should they be able to login with their own Office 365 / domain account to access the site? (without creating a "Microsoft personal" account)
b) Do they need to create a "Microsoft personal" account.
As we probably all know, there's a massive number of bugs in the SharePoint login/invitation system, so I'm not even sure if what we're trying to do should work or not when trying to troubleshoot these issues for users.
We're having issues with users being rejected for "not being found in directory" and other issues, which I can troubleshoot myself, but it's very hard to even start when I don't even know the answer the question I'm asking here.
I would appreciate if this question does not get shut down based on one of the crazy pedantic rules of these sites, because it's a very clear technical question with a right/wrong answer that will help other people. Leaving it up and not allowing answers makes zero sense. I've scoured the web for hours to try and find a definitive answer to the question, but can't find one.