Job failed randomly

The ledger data import job imports data from Ledger database and loads into a cube called GL_BUD.This job fails randomly with no pattern /frequency stating "network error" and creating an exception file in the server .When this job is rerun again after sometime, it ran  successfully.

PFA of the error report in the query.

The reason of failure couldn't be identifies as the job runs successfully in the next run.

Please help me in understanding the most probable reason for its failure and necessary steps to be taken to avoid it in future.