Analyze in Excel for External Users

A Power BI Pro user outside my organization can use reports I have shared to them via Power BI Service, but when they select 'Analyze in Excel', the user receives a 'Forbidden Activity ID' error message within Excel, then they are rerouted to the Microsoft sign in screen. From the sign in screen, their current password and email address does not work. Please allow users outside the organization to utilize the Analyze in Excel function since it is available.