Configuring Trusted Connection
Veeam ONE uses TLS to ensure secure data communication between Veeam ONE Web Client website and a web browser.
In case you installed a self-signed certificate, when you try to access Veeam ONE Web Client from a remote machine, the browser will display a warning notifying that the connection is untrusted (although it is secured with TLS).
To eliminate the warning, import the self-signed certificate to client machines (the machines from which you plan to access the Veeam ONE Web Client website).
For details on importing TLS certificates, see this Microsoft Learn article.
For details on Veeam ONE certificates, see Appendix C. Veeam ONE Certificates.