You may get this error. My provider does air gap behind the scenes. You can disable this with the below registry change-
Your service provider has implemented backup files protection against deletion by an insider for this cloud repository. To protect against advanced attack vectors, we recommend that you configure your cloud backup jobs to keep multiple full backups on disk (as opposed to forever-incremental chain with a single full backup).
New-ItemProperty -Path 'HKLM:\SOFTWARE\Veeam\Veeam Backup and Replication\' -Name 'CloudConnectBinGfsNotificationSeverity' -Value "1" -PropertyType DWORD -Force