Why is Auth0 allowing duplicate records in our Auth0 account? Very strange and it seems to be causing some issues.
Note to Auth0, I can provide you the duplicate user list via PM if you’d like.
For database connections and as you mentioned this should not be allowed and I did a few manual and also API tests and trying to create users with the same email will indeed trigger an error so the validations are being applied. However, with software there’s always a possibility of edge cases and infrequent conditions gathering to lead to issues. I reviewed your particular situation and noticed that the duplicate users that I could find were all created in the same exact date and in a very small time window which suggests to me that your performed a user import to Auth0 possibly using the user import jobs.
Since the time you executed the user import and now there was also changes introduced, in particular, with the amount of users that can be imported at once. I’m mentioning this because if you imported a significant number of users at the same time with multiple jobs or with duplicates within the same job the sheer number of users could have lead to some race condition that then triggered the duplicates. We’ve since reduced the number of users that can be imported in a single job so these hypothetical conditions are now even more unlikely to occur.
As a mitigation for the problem you’re observing I would suggest you to use the Management API or even the Dashboard (if the number of users with issues is low) to delete one instance of each duplicated users pair. In particular, you should delete the instance that although created was never used/updated and never actually performed a login. Apologies for the inconvenience of having to perform this cleanup.
I have the same issue with my users. After starting using Auth0 to authenticate, I detected one user account that was duplicated. I know that in the job to import the users there were duplicates. I know that there are 3 accounts duplicated, but only 1 of them failed and the others are working ok. I tested the same situation 2 weeks ago and by that time everything was working pretty well.
We solved the problem deleting the account that has never logued in and the user now can use the system normally.