Can't access share sometimes and some strange performance issues

I'm getting error 0x80070043 "The network name cannot be found" when accessing \\dc01 (the root), but can access shares via \\dc01\share.

When I get that error I also didn't get the network drive on hosted that server set via Group Policy, it fails with this error:

The user 'W:' preference item in the 'GPO Name' Group Policy Object did not apply because it failed with error code '0x80070008 Not enough storage is available to process this command.' This error was suppressed.

The client is Windows Server 2012 Remote Desktop and server is 2012 too. On a VMware host.

Then I log off and on, and no issues.

Maybe related and maybe where the problem is: When I have this issue and sometimes when I don't (the network drive is added fine) I have some strange performance issues on share/network drive: Word, Excel and PDF files opens very slowly. Offices says "Contacting \\dc01\share..." for 20-30 sec. Txt files don't have that problem.

I have a DC02 server also 2012 with no issues like like this.

Any tips how to troubleshoot?

I've changed the drive mapping to the FQDN of the server, and haven't has any issues since.