What is the process to restore network connections for network file shares on Windows 2019 Server

I did disconnect the mapped network drive on the server and restarted the server and no change in restoring the file share. The mapped share is now gone from the list of file shares on the server.

the net use commands are not working.

C:\WINDOWS\system32>net use R: \\Nas-1.nea.gov\photo
R: has a remembered connection to \\Nas-1.nea.gov\ora. Do you
want to overwrite the remembered connection? (Y/N) [Y]: Y
System error 64 has occurred.

The specified network name is no longer available.

This is a NAS (IBM EMC) device that houses the file shares in question is 

using the NETBIOS file sharing protocol.