RP4VM 5.3 vcServerUuid is marked @NonNull but is null

Hi RP Experts,

I'm having the following issue "vcServerUuid is marked @NonNull but is null" when try to protect a VM from RP4VM ver.5.3 Menu. is a Standalone ESXi ver. 7.0, new installation.

I've followed the following kb https://www.dell.com/support/kbdoc/en-us/000081499/after-protecting-vm-through-html5-plugin-from-a-standalone-esx-error-are-seen-sometimes-on-attempting-to-protect-vm-running-on-esxi-which-are-part-of-a-cluster-the-error-shown-states-vcserveruuid-is-marked-nonnull-but-is-null 

btw Flex plugin isn't supported in vSphere 7.0, only HTML plugin. is there any way to by pass this issue? or maybe RP4VM doesn't support a single ESXi node.

thanks,