System Error 64 occurs when I map a network drive

I mapped the drive of the server used by me, (D:), to a virtual drive in my notebook as (Z:). It worked well all along.
In order to enable all the port of the server, Dongsheng helped to add a netwok card to that server machine meanwhile disabled the original virtual one. Thus, the network address of that machine is changed from an local one to an external. Because of this, the mapped drive is out of work.
When I tried to map the same storage via the new external address, some error occurred. It is "System Error 64:The specified network name is no longer available."
Dongsheng told me the machine had not been recognized as a local one any longer when its virtual NIC was disabled. That's why the mapping doesn't work. Even it is mapped to my notebook successfully, it isn't safe because the address is external, which is easy to attach.
It is a new knowledge to such a green hand like me. So I recode it in detail.
By the way, the command I used to map network drive is "net use * //server/D$ ". Be careful of the blanks before and behind "*".