Referring to this Q&A: OneDrive External Sharing Does not ask for access code?
External sharing works as described, but afterwards there is no guest user created in the tenant and for every subsequent share instead of asking for a verification code the external user is propmpted to sign, only to receive the following error:
"AADSTS90072: User account 'xxxxxx' from identity provider 'live.com' does not exist in tenant 'xxxxx' and cannot access the application '00000003-0000-0ff1-ce00-000000000000'(Office 365 SharePoint Online) in that tenant. The account needs to be added as an external user in the tenant first. Sign out and sign in again with a different Azure Active Directory user account"
What could be the cause? This happens with recipients that have MS consumer accounts.