Problem statement
When using account linking, what will happen if a user from a GitHub connection has an email such as Test@example.com, but their Gmail is test@example.com. Will the case difference prevent these accounts from linking?
Solution
If using the Account Linking Extension rule, this uses the /api/v2/users-by-email endpoint of the Management API to return user accounts with the same email. Since this is a case-sensitive search, and Auth0 stores emails from upstream IdPs with the case preserved, Account Linking fails for accounts where the email is the same but with different capitalization.
If linking accounts with the Management API, there is no requirement for emails to match on the two accounts.
https://auth0.com/docs/api/management/v2/users/post-identities