How to fix Amazon RDS database that is in anInsufficient-resource-limits

I am having some issue with our AWS Aurora PostgreSQL RDS DB. DB instance status is in Insufficient-resource-limits state.

Screenshot of the console:

The error in the CI to the RDS update:

 Error: waiting for RDS Cluster  create: unexpected state 'insufficient-resource-limits', wanted target 'available'. last error: %!s(<nil>)

I don't have enough info to debug, I checked all my service quota & nothing seems exceed the limits

Solution

I opened a case to AWS Support, & it was the number of Custom endpoint per Cluster.

"An Aurora DB cluster has no custom endpoints until you create one. You can create up to five custom endpoints for each provisioned Aurora cluster."