Disconnects in FIX connections in local network

Question

I have a FIX server and FIX client implementing FIX4.4 running on the same network. I use QuickFIX C++ engine. Altough they are on the same network, sometimes they disconnect. In the FIX server's event logs:
20140612-01:21:30.000 : Sent test request TEST
20140612-04:11:56.000 : Sent test request TEST
20140612-07:05:26.029 : Sent test request TEST
20140612-07:05:26.029 : Socket Error: An established connection was aborted by the software in your host machine.
Means HEARTBIT messages are failed to send/recv.
What can be wrong? I have a regular setup and nothing special..
Thanks

Answer 1

while the client connection was accepted by the server, it doesn't look like you then achieved "logon". First you connect, then you logon. You need to make a logon request after you connect. Look at the initial FIX messages sent between client and server.