Can an anchored vessel be Not under command according to Navigation Rules?

No, a vessel anchored cannot be a "vessel not under command"..

International / Inland

Navigational Rules of the Road

General definitions

Rule-3

For the purpose of these rules, except where the context otherwise requires:

(f) The term "vessel not under command" means a vessel through some exceptional circumstance is unable to maneuver as required by these rules and is therefore unable to keep out of the way of another vessel.

This may apply to a vessel underway, NOT making way. Please refer to the link below.