HyperBackup task fails only when Windows Server 2019 virtual machine on ESXi is online.
If the target virtual machine is shutdown, the backup succeed.
When a virtual machine is configured with UEFI, the creation of VMware quiescing snapshot failed due to the following article.
1)Reinstall Windows Server 2019 with BIOS and MBR configuration referring to VMWare article Workaround Option 1.
2)Install Server Edition of Virtual Edition on the target VM.
Run backup using the normal agent method.
3)This issue is resolved in Windows Server version 1809 and all versions of Windows Server 2019 OS Build 17763.1012.
– ActiveImage Protector 2018 HyperAgent