F5 backup fails in NCM

Hello All,

We have F5 Devices in NCM for backup. It has stopped taking backup saying error "Connectivity issues". Backup is successful only for two F5 devices out of 12 which are standby.

We have checked, Device configuration, all settings & F5 Template is same for all working and non-working devices.

Checked with Solarwind and F5 OEM, but received nothing specific which will address the issue.

Anyone can suggest, what could be the issue.

Thanks in advance...!!!