could you provide some additional information? It's not clear where exactly you're seeing this error and what you're trying to do.

This error message is on the backup application.
So install app on Server 2012, create backup plan. Run this plan, error pops up. See screenshot

Where are you sending the backups? What version are you using?

I am sending it to a S3 compliant storage. This works on my other systems, Windows 10, Windows Server 2019.

Public v6.3.4.38

You may want to check and make sure both TLS 1.0 and 1.1 are enabled on the system according to this article: https://docs.microsoft.com/en-us/windows-server/security/tls/tls-registry-settings#tls-10

If that doesn't work then I'll have to ask you to open a support case since it's very tough to diagnose these types of issues on the forum.

I Changed the registry entries and rebooted the server.
Still the problem persists.

Please open a support case from the agent using the Tools - Diagnostic toolbar option and please reference this forum post when submitting the logs. Thanks.