I have one job. The job runs successfully. In case of error, i have one recovery checkpoint in place to retry the job at a particular point. If i try to launch a recovery checkpoint, i have a stacktrace on the TAC log and on the JobServer log. The final message on TAC job conductor is "Connection to server failed". Which server ?
The recovery checkpoint works well in the customer environment. So, the job itself is not in cause.
Could you please open task recovery module on the Task Execution Monitoring page, which provides a lot of details, such as the failure instructions provided in the Job design, the point of restart, your component and the error that the Job encountered.