We are trying to use Aura from GCP, but when attempt login get this error.
It looks like you are already registered. Please log in with the same method you used when you first registered. If this doesn't solve your problem, then please contact our support team.
You will need to contact Neo4j Aura support, and let them know you saw this article, and they need to reset your authentication method. After the reset, it may take about 15 minutes, but your login from GCP will work correctly.