Notably, in recent hosted versions of Exchange that has been resolved since they can use Azure AD to authenticate across tenants, and if you don’t have Office 3

Notably, in recent hosted versions of Exchange that has been resolved since they can use Azure AD to authenticate across tenants, and if you don’t have Office 365 you can make a temp account in their tenant when you click on the link to see the email. It works fine (unless you’re still on-prem for email).