AUTH0 issues - could anybody give us any advice on the below AUTH0 issue?

Hi, could anybody give us any advice on the below AUTH0 issue?

we use Auth0 for login, although they are separate autonomous Auth0 accounts.

Our members log into BIOConnect, the member’s online area, and BIOP members log into Bio World online (the monthly magazine).

For both Auth0 accounts, when members holding a forename.surname@bio.com account use their email to log in to BIOConnect or verify for BIOP Biology World Access, they never receive the email.

thanks, a lot