create linked server connections using hostnames and FQDNs for RDS MSSQL Instance

Presently, we are only able to successfully create linked server connections using the IP address of the target systems; using hostnames and FQDNs does not work. We need to use FQDNs in order to support cluster/AAG failover of SQL servers.

Can someone provide any guidance resolving current issue or ways to setup the Linked server connections using FQDN and hostname?

i have reviewed the below solutions as well, but not sure how it is useful in this case:

1. https://repost.aws/knowledge-center/rds-sql-server-create-linked-server
2. https://aws.amazon.com/blogs/database/implement-linked-servers-with-amazon-rds-for-microsoft-sql-server/