TLDR – If you are not interested in how the PowerShell script works and just want to jump straight to the solution see the PowerShell script below; just be aware that the script only works when moving a VM to another vNET in the same subscription. To move a VM to a vNET in another subscription you need to follow a different process which will be documented in a future blog post; let me know in the comments if you’d like to see this happen. Moving an Azure VM to another vNET isn’t easy You’d think that since VMs move around a lot on networks that moving an Azure VM from one vNET to another in would be a simple task… it is not. In fact, Microsoft’s official view on this approach is that they do not support it – so this means you are left to figure it out for yourself.
Backup to URL: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel
When performing an SQL backup using the feature “backup to URL” in, you receive the error: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel or Backup to url received an exception from the remote endpoint Essentially what this error is saying, is that the certificate being used is not trusted.