User is not recognised in wordpress app embded in an iframe in a vueJS app

We are using Vue JS app and WordPress app. and have just implemented Auth0 for both of them.

The Vue JS app has a WordPress booking plugin added in an Iframe. Auth0 login is recognized by the booking plugin in the IFrame if I login into WordPress in a separate browser tab. However, login is not recognized if I log in to the Vue JS app.

Please advise a solution to resolve this issue.