Oracle TNS-12535: TNS:operation timed out

Hi,

I am using Oracle 11g. For many years I could connect to the database server from any remote machine.
But from yesterday I am getting error "TNS-12535: TNS:operation timed out" error when I do tnspping <<service name>> from any other machine and not able to connect to the database.

I am able to connect to the database by directly login to the server. OS of the database server is Windows Server 2008 R2 Enterprise edition.

I disabled the firewall on the database server machine by following the below steps.

1.Open an Administrator: Command Prompt. To do so, click Start, click All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.


2.If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.


3.At the command prompt, type the following command:

netsh advfirewall set  AllProfiles  state off

from the link
https://technet.microsoft.com/en-us/library/cc766337(v=ws.10).aspx

But no use.

Can you please suggest if I can do anything else to resolve the issue.

Thanks.