I have external access enabled on a site collection in my tenancy, and was previously able to invite external users to the site successfully, but now when I attempt to add external users nothing happens.
I don't receive any error messages, so it appears that the invitation has sent, only the user never receives the email. When I go to the
Access requests and invitations page they are not in the
External User Invitations list.
I set up a dummy Outlook account and was able to grant access to that user, but other domains aren't working.
However, I have added users from other domains in the past, so I can't understand why it worked for some users and not for others?