Just to confirm, you are using MSP360 Managed Backup and have set up these storage accounts from the management console. You are using the Amazon S3 and Wasabi storage connectors and not the generic S3 connector. When you run a backup to either storage account, you see the error posted, correct?

Are you using a Windows agent? If so, is it a server or desktop? Version?

I think you'll have a much easier time working with Support on this one. I see only one reference to this error for Google Cloud that was addressed some time ago. It could be a TLS version issue, but in order to understand the error, the Support team is going to need to see the logs and system configuration. I would use the Tools - Diagnostic toolbar option on the agent or the RMM - Remote Management - gear icon on the endpoint in question - Send Logs option from the management console to get the support ticket created.

we have one Windows server 2016 and the rest are Windows 10 desktop. I will send the the send logs to the support team. Thank you