primary Domain Controller for this domain could not be located

Well if you can RDP to another computer it doesn't matter.
If you can't connect to the PDC try to reset it (open cmd shutdown -r -t 0 -m \\pdchostname

If it gets back it will be good and then you can figure out on the event viewer, just make sure that ipv6 is enabled.
make sure to use ping 127.0.0.1 to test the nic if it fails then change the NIC (network hardware)

still the same not able to connect to PDC.

Well you need to go onsite and check.

Is the remote DC switched on ?

Do you have any out of band management for the remote DC ?

Are you able to connect to the remote DC from another computer at the remote site ?

Hi,

1) Hope you can ping the PDC?
2) Are you able to access the shares on the PDC? Try (\\Pdcservername\c$) and see if you are able to access it. Otherwise there are chances for a secure channel broken.
3) When you run "dcdiag" from your PDC (or additional DCs), are you seeing any errors?
4) Check if NETLOGON service is started?

Thanks,
Abhi...

Hi

On this fileserver to which you can connect, what is the result if you open cmd prompt as admin and enter:   quser /SERVER:remotedcname
If it shows you active sessions kill them by running  logoff session number like:   logoff 2 /SERVER:remotedcname  

The above will clear any sessions that hangop the DC.

Cheers

IPConfig /ALL
PING DC Name
PINC DC IP -4

Select allOpen in new window

Anything work?

@PhilipElder, if specifying an IPv4 address to ping, addign -4 does nothing, If a hostname is used however...

Have you go onsite as I proposed earlier?
Because if the server is up then it's a networking issue on site.

So in conclusión you will never be able to connect until you solve the flow into the server.

So did you test if you could "Ping the server" ?