The message indicates that the connection to LO expired while waiting for something to happen in CRM.  SQL snaps can be gathered during the time frame the process was running to determine where the performance issue occurs.  This can also be reviewed using the Business process history data list in CRM.  If the batch commit portion is taking a long time take the following action:

1.  Edit the constituent sync.
2.  Go to the advanced tab and check the download batch size.
3.  Set it to 100 if batch commits are taking longer than 5 minutes.

If the performance issue occurs with the constituent export, updating to the latest version of the sync would potentially address the issue.  Create a case and include the version of the sync you are currently on (How to determine the version of the LO Sync) to determine if a later version is available.