Creating a GTM Pool error

I am trying to add a GTM pool with the following command

create gtm pool a POOL_NAME { members add { DC:/Common/VS_NAME { member-order 0 } } }

It is giving me this error:

01070226:3: Pool Member VS_NAME references a nonexistent Virtual Server

The virtual server does exist.

I have added 40+ other pools with the same command, this is the only one giving me an error.

When I try to create the pool via the GUI this server is not available in the "Virtual Server:" dropdown list.

What could be the issue?