There is a misleading certificate error log present in backup logs when insecureSkipTLSVerify is set as "true".
DPA:

~~~

apiVersion: oadp.openshift.io/v1alpha1
kind: DataProtectionApplication
metadata:
  name: velero
  namespace: openshift-adp
spec:
  backupLocations:
  - velero:
      config:
        insecureSkipTLSVerify: "true"
        profile: default
        region: us-east-1
        s3ForcePathStyle: "true"
        s3Url: https://s3-openshift-storage.apps.abc.in
      credential:
        key: cloud
        name: cloud-credentials
      default: true
      objectStorage:
        bucket: bucket-data-7ae6eebf-1111-4444-b105-4a44d7c07df3
        prefix: velero
      provider: aws
  configuration:
    nodeAgent:
      enable: true
      uploaderType: kopia
    velero:
      defaultPlugins:
      - openshift
      - aws
      - kubevirt
status:
  conditions:
  - lastTransitionTime: "2024-01-23T07:16:34Z"
    message: Reconcile complete
    reason: Complete
    status: "True"

~~~

With  insecureSkipTLSVerify: "true", SSL/TLS security is disabled.
Still the velero backup logs shows below error:

~~~

An error occurred: Get "https://s3-openshift-storage.apps.abc.in/bucket-data-7ae6eebf-1111-4444-b105-4a44d7c07df3/velero/backups/mybackup/mybackup-logs.gz?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=tiZrwemXjFgPe2NLIWWX%2F20240123%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240123T072103Z&X-Amz-Expires=600&X-Amz-SignedHeaders=host&X-Amz-Signature=d58a3f11111111111e63e2cc77fc24073ada5bf5a70507c4cf01b46d72018f8": tls: failed to verify certificate: x509: certificate signed by unknown authority

~~~
Even backup is completed. Backup describe output:
~~~

Name:         mybackup
Namespace:    openshift-adp
Phase:  Completed
Started:    2024-01-23 07:17:21 +0000 UTC
Completed:  2024-01-23 07:17:54 +0000 UTC

Total items to be backed up:  11
Items backed up:              11

Resource List:  <error getting backup resource list: Get "https://s3-openshift-storage.apps.abc.in/bucket-data-7ae6eebf-1111-4444-b105-4a44d7c07df3/velero/backups/mybackup/mybackup-logs.gz?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=tiZrwemXjFgPe2NLIWWX%2F20240123%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20240123T072103Z&X-Amz-Expires=600&X-Amz-SignedHeaders=host&X-Amz-Signature=d58a3f11111111111e63e2cc77fc24073ada5bf5a70507c4cf01b46d72018f8": tls: failed to verify certificate: x509: certificate signed by unknown authority>

~~~

This velero backup log seems misleading.

We tried to set the CA with insecureSkipTLSVerify: "false" and caCert with correct CA for s3Url but still error came.