TenantID blocks login

It turns out, the default case for the auth provider doesn't seem to work correctly, and folks need to specify a tenantId to get access. A quick workaround is to show a tenantId box before login :/

We should scour the docs and see what we're getting wrong here - surely AAD isn't expecting folks to input their tenantId....right?

Start by reviewing the authentication documentation and the default auth-provider behavior in this TypeScript project. Confirm how Azure AD handles the default case and determine whether login can work without asking users to enter a tenantId.

Written by the indexing model from the issue text.