SQL 2008 error

[contact1185]

A Transport-level error has occurred when receiving results from the server. Provider TCP provider error 0 The specified network name is no longer available. 

This error has started occurring today on all clients having MS-SQL 2008. Few computers are linking but rest are not. 

What could be the reason? Kindly explain.

[#2]

Hello,
This means that SQL Server is not accepting incoming connections .
Can you connect locally from the SQL machine ?
and I see you cannot connect from remote computers. test if TCP Port 1433 is open
you can either try with telnet

TELNET Servername 1433

Or Powershell
https://www.sqlshack.com/powershell-sql-server-validation-utility-dbachecks/

also make sure that the windows firewall on the server is allowing TCP 1433
Also, check the CPU usage on the server, sometimes when server is extremely busy it stops accepting incoming connections

[#3]

@Javier_Villegas 

Thanks for the reply.
Can you connect locally from the SQL machine ?   yes 
This issue is coming in all clients using sql-2008 versions, 3-4 PC are working but rest not.

however I will get 1433 checked.

regards,

kamal

[#4]

@contact1185 

Hi Javier, I see in the taskbar that this PC has no internet connection, it may be a DNS problem, see if doing a:

PING SERVER_NAME 

Resolves to the IP address, if it does not resolve it, try changing in your connection string SERVER_NAME directly to the IP, obviously of course before testing if you can PING and then TELNET IP 1433 to rule out a network connectivity problem.

[#5]

The issue is solved I think our software firewall and antivirus application were giving problems. As soon as it was deactivated, PC's started linking. The issue has been raised to the vendor. Thanks for the support, I appreciate the platform and quick help.