Hi everyone,
This issue has been resolved.
A DevOps engineer helped us identify and fix these small mistakes:
Single-node server:
The root user password for the PostgreSQL database was reset.
Both credentials (root and user) were provided in the maintenance configuration screen.
Additionally, the database user was incorrectly set to postgress instead of fusionauth—my mistake!
Digital Ocean one-click app instance (3 Kubernetes nodes):
The database host was populated incorrectly. In our case, changing it to db-postgresql solved the issue.
Similar to the single-node server, we also reset the root password and provided both credentials.
This could be helpful for future reference.
Thanks