Explanation
Database backups can fail for various reasons. Typically, a backup fails because either the database host cannot access the object store, or there are problems on the host or with the database configuration.
First need to determining the Problem
In the Console, a failed database backup either displays a status of Failed or hangs in the Backup in Progress or Creating state. If the error message does not contain enough information to point you to a solution, you can use the database CLI and log files to gather more data. Then, refer to the applicable section in this topic for a solution.
Database Service Agent Issues
Your Oracle Cloud Infrastructure Database makes use of an agent framework to allow you to manage your database through the cloud platform. Occasionally you might need to restart the dcsagent program if it has the status of stop/waiting to resolve a backup failure.
Object Store Connectivity Issues
Backing up your database to Oracle Cloud Infrastructure Object Storage requires that the host can connect to the applicable Swift endpoint. You can test this connectivity by using a Swift user.
Host Issues
One or more of the following conditions on the database host can cause backups to fail:
- Interactive Commands in the Oracle Profile
- The File System Is Full
- Incorrect Version of the Oracle Database Cloud Backup Module
- Changes to the Site Profile File (glogin.sql)
Database Issues
An improper database state or configuration can lead to failed backups.
- Database Not Running During Backup
- Archiving Mode Set to NOARCHIVELOG (When you provision a new database, the archiving mode is set to ARCHIVELOG by default. This is the required archiving mode for backup operations)
- Stuck Database Archiver Process and Backup Failures
- Temporary Tablespace Errors
- RMAN Configuration and Backup Failures
- RMAN Retention Policy and Backup Failures
- Loss of Objectstore Wallet File and Backup Failures
TDE Wallet and Backup Failures
- Incorrect TDE Wallet Location Specification
- Incorrect State of the TDE Wallet
- Incorrect Configuration Related to the TDE Wallet
- Missing TDE Wallet File
As this is not new provisioned database and already in the ARCHIVELOG , regular backups of DB system to OCI object storage in places, so the best answers are,
- Ensure that your database host can connect to the OCI object storage
- Restart the database service agent

Explanation
All databases created in Oracle Cloud Infrastructure are encrypted using transparent data encryption (TDE).
Oracle Cloud Infrastructure encrypts all managed backups in the object store. Oracle uses the Database Transparent Encryption feature by default for encrypting the backups. and the customers can manage the TDE Wallet after DB Systems are provisioned.

https://docs.cloud.oracle.com/iaas/Content/GSG/Tasks/loadbalancing.htm#Create Enter the Health Check details.
Load Balancing automatically checks the health of the instances for your load balancer. If it detects an unhealthy instance, it stops sending traffic to the instance and reroutes traffic to healthy instances. In this step, you provide the information required to check the health of servers in the backend set and ensure that they can receive data traffic.
Protocol: Select HTTP. Port: Enter 80 URL Path (URI): Enter / The rest of the fields are optional and can be left blank for this tutorial.
Click Create.