How to automatically authenticate a user in app2 when he is authenticated in app1

We have a asp.net application, which authenticates users through Auth0. Once the user is authenticated, there is a link to a different django application that also uses auth0. But both applications connect to different tenants and the user has to login twice.

How can we authenticate the user automatically in the django app, if the user is authenticated in the asp.net app?

I don’t think there is a way to do this, or no easy way at least.

What is the use case for having two separate tenants?