How to backup a virtual machine with ubuntu in AZURE?

Question

Backup

I can’t set up backup of a virtual machine from ubuntu in AZURE
In ubuntu, the agent from azure is installed:
"waagent -version
WALinuxAgent-2.0.8 running on Ubuntu"
But when I try to register the virtual machine in the backup repository, it says "The virtual machine agent is missing in the virtual machine." Install the prerequisites, VM agent and restart the operation. "