Hello,
Our company is using Microsoft's external user feature to set up sharing folders in our SharePoint Online instance for our customers. Our security settings require them to be added to our Active Directory as an external user, upon which they will receive an email inviting them to either use an existing Microsoft account or create a new Microsoft account to access our SharePoint. Once in, we grant them permission to a specific folder and we're good to go.
So far, all of our customer partner users have been able to set up their accounts successfully with the occasional fixable user error here and there. However, for one of our customers, they are seeing the following error when they click the "Get Started" link in the email they receive after being added to Azure AD.
I have no idea why this is occurring. It happens when I click on the link as well, which is not true in other cases, leading me to believe there is something wrong with the invitation being generated.