Details entered by user are not captured in database

In Adobe LiveCycle ES2, sometimes when a user submits the form from workspace, details entered by the user are not captured anywhere in database (SQL 2008). There is no exception in server log at the specified completion time so we couldnot track the exception. With the same scenario we have many successful process which passed the same step. we are facing this issue in almost all the forms nowadays. I guess it will not be a probelm related to form or workflow. Any suggestions would be a great help for us..

Thanks,

Gayathri.