Couldn't add <external email address> as a member.

[Scott Dart]

I'm trying to put a Sharepoint group together.  I'm attempting to add an external user (I've done this many times before) but this time I keep getting the error message "Couldn't add <external email address> as a member." 

I can't add them in Outlook, I can't add them in Sharepoint.  I tried adding them in Azure Active Directory, and I successfully "invited" them, and added them to the group in AAD.  Still no joy, though, when I go into Sharepoint, it doesn't list them as part of the group, and when I try to add them to the group, I get the same error message.

I'm tearing my hair out here.  I need this group active tomorrow, and this user is the chair of the group.  What am I missing

[#2]

@Scott Dart 

Using the Share button in the SharePoint site is that the error you get "Couldn't add as a member"?  Screenshot would be good to see. 

Have you checked the SharePoint site is setup for external access in the SharePoint Admin centre, sounds like you have if you have done it before but just wanted to check. 

[#3]

@Andrew Hodges Thanks for that.  Yes, I checked that before posting here. :)  But it's a fair question, and one that I would have asked if answering in a thread.

I think I'll probably just nuke this Sharepoint site and try again.

[#4 · Accepted solution]

@Scott Dart 

Do you need a Microsoft 365 Group creating or just access to the SharePoint site? I would give that a go, just create a Team Site without a group attached and add them from there, its the option I use the most as I am not a fan of Groups, but that's maybe just me.  No idea why it wont work for you but may get you up and running. 

[#5]

@Andrew Hodges I think it was an AAD thing.  The next morning, I looked, and all was well.  I wonder if I didn't just give it enough time to propagate to everywhere it needed to.  Seems to be fine now.

Thanks for your help!