Error on listen function:network name can not be used

Hi,Below error is continously appearing on our one of the Domino Server.

"Error on listen function: Network name cannot be used

Listner task for port LAN0tcpip is suspending for 20seconds due to listen errors"

I searched for the solution in the forum & I found that it happens due to mismatch of Domino Server document FQDN with Machine’s FQDN.

But here in this scenario I found that

In My Computer properties- Network Identification on this server:

faxserver.sap.abc.com

Domain: sap.abc.com

&

Information from Server Document of this Domino Server

ServerName: lotusfax01/abc

Domain Name: abc

FQIHN:faxserver.sap.abc.com

I this case both FQDN are same. I also added LAN0tcpip as a disabled port in notes.ini for this server. After that error was diappeared for 1 week. Now again it is continously appearing on console.

Pls check & verify above given information & pls suggest what could be wrong.

Thanks in advance.