Use any of these two workarounds:

• Use path style URL to access bucket: Since path style URL adds bucket as part of URL path and not as hostname, we did not get any SSL issues even for buckets with a . (dot) in the name. However, NetBackup default configuration uses Virtual style for all dual stack URLs like s3.dualstack.<region-id>.amazonaws.com. We can add older s3 URL as path style and can connect with bucket with a (.) in the name. To do this we can add region with plain s3 endpoint (s3.<region-id>.amazonaws.com) and selecting URL Access Style as path style.

• Disable SSL: This workaround is not the recommended one since it replaces the secure endpoint with unsecure/unencrypted endpoint. After turning off SSL it disables peer host validation of server certificate. It bypasses the hostname match for virtual host style URL of bucket (bucket.123.s3.dualstack.us-east-1.amazonaws.com) with subject name in certificate (*. s3.dualstack.us-east-1.amazonaws.com).