Federico is an external user from another company that needs access to SharePoint resources on our company side, mycompany.com. I'd rather have him access our resources via Microsoft Teams on the web because that's the user experience I want to give him. However, though I grant him guest access using his Erik@hiscompany external e-mail address, both the SharePoint web interface and Teams will request he logs in using a password.
We had a similar situation with Myrtle as well in the past. She's another external contractor. I tried allowing her in as,
- Her original Myrtle@hercompany.com email--but since this understandably has no credentials within our domain and thus no password, she couldn't get in at the login prompt
- A new, personal Myrtle@outlook.com address we created for her uniquely for this purpose so she could actually have a password to login with as it seemed SharePoint/Teams does allow a Microsoft email address to login via the credentials prompt
- A company-assigned Myrtle@mycompany.com username/password I gave her within our domain
Ultimately, after trying unsuccessfully to grant her access to the files she needed with the first two methods, we ended up giving Myrtle a mycompany.com login (the last email address assigned to her, per the above). That worked, but didn't fully satisfy me as now it might seem as though she's employed by us--which she is not.
Federico’s trouble accessing our resources now might be similarly best resolved by granting him the same--a mycompany.com address within our domain. But is this truly my best and only option?
I know I gave Myrtle an Exchange mailbox with a mycompany.com email address, so that she can use our calendars, browse our Teams folder structure, etc. I set up a contact for her in my ActiveDirectory with what amounts to a dummy internal address and her personal external mail address. All this worked. I suppose I could likewise create and set Federico's dummy internal e-mail account to forward to his @hiscompany.com address also, and then just hide his dummy contact from the GAL afterwards.
Is this what others recommend as well?