'Failed to connect Kasten k10 instance', to the Veeam Backup & Recovery server 

This article explains how to resolve the SSL connection issue while adding K10 instance to the VBR server

Issue description: 

Adding Kasten K10 instance in VBR fails with the error `The SSL connection could not be established, see inner exception`. 


VBR V12 introduced support for Kasten by K10 Plug-in, which integrates adding a Kasten instance under the backup infrastructure and monitor the policy runs through the VBR console.

To add K10 instance to the backup infrastructure of VBR, a hostname for the K10 UI and the token from the serviceAccount are required. 

VBR supports the use of HTTPS endpoint only for security reasons, for adding the K10 instance.

When K10 instance is added, Veeam Backup & Replication checks the certificate that is used to access the K10 dashboard. If the certificate is not trusted, Veeam Backup & Replication will display a certificate warning. 

The error The SSL connection could not be established, see inner exception usually means that the VBR could not establish an SSL connection to K10 instance. 

Logs from the Kasten K10 plugin of VBR shows that the K10 URL gives an unexpected thumbprint. 

Warning The certificate has unexpected thumbprint [F59EB5E15B91BE257EB58D295B77417D6F3CED71]. 
Requested address [https://kasten-10.xxxxxx.example.com/k10/vbrintegrationapi-svc/v0/server

This means that there was an issue with the certificate verification in Kasten K10 plugin even though the certificate was proper for the K10 URL. 

The SSL connection could not be established, see inner exception, error was seen before the certificate warning message, even after the certificate was added to windows trusted certificates. 


This issue has been fixed and a new plugin upgrade is available at https://www.veeam.com/download_add_packs/vmware-esx-backup/kastenplugin/ (requires registration)