TCP/IP socket Error -989


I am using Q24Plus.

It is sending data to the server every 1 minute. size of data is 200 bytes.

Some times it is giving Error on socket and the error number is -989 the meaning of the error in WIP doc is WIP_CERR_HOST_UNREACHABLE that means no route to host.

Now my question is.

Is this due to problem in network?

Is this due to problem in our server?

Is this problem due to modem socket connection to our server?

Please help what is the exact problem?