ESXi 7.0 free and XSIBackup free

Hello,

I need your help.

I want using XSIBackup Free on ESXi 7.0.

Backup  working correct, but problem is with email notifications.

XSIBackup must be able to make a change to the file:  /etc/vmware/firewall/service.xml

If I try to change the permission manually (from 444 to 644), ESXi will return this error message:

[root@HPMicroS01-ESXi70:~] chmod 644 /etc/vmware/firewall/service.xml

chmod: /etc/vmware/firewall/service.xml: Operation not permitted

[root@HPMicroS01-ESXi70:~]

Thx. for help.