Error de Timeout en Generación de Planilla

A que se deberá el siguiente error que aparece en el Log de la planilla, este tarda 20 min hasta que da el error y se cancela la generación (Versión Evolution 1.10.0.7) :

System.Data.SqlClient.SqlException (0x80131904): Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.

ultima planilla empleado: 3156 16/05/2017 ---> System.ComponentModel.Win32Exception (0x80004005): The wait operation timed out
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite)
at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, String methodName, Boolean sendToPipe, Int32 timeout, Boolean asyncWrite)
at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.<NonQuery>b__0(DbCommand t, DbCommandInterceptionContext`1 c)
at System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch[TTarget,TInterceptionContext,TResult](TTarget target, Func`3 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed)
at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.NonQuery(DbCommand command, DbCommandInterceptionContext interceptionContext)
at System.Data.Entity.Internal.InterceptableDbCommand.ExecuteNonQuery()
at System.Data.Entity.Core.Objects.ObjectContext.<>c__DisplayClass59.<ExecuteStoreCommand>b__58()
at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)
at System.Data.Entity.Core.Objects.ObjectContext.<>c__DisplayClass59.<ExecuteStoreCommand>b__57()
at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation)
at System.Data.Entity.Core.Objects.ObjectContext.ExecuteStoreCommand(TransactionalBehavior transactionalBehavior, String commandText, Object[] parameters)
at System.Data.Entity.Core.Objects.ObjectContext.ExecuteStoreCommand(String commandText, Object[] parameters)
at Aseinfo.VH4.WindowsServices.Salarios.Repository.GenericEntityRepository.ExecuteStoreCommand(String sql, Object[] parameters) in c:\BuildAgent\work\89066541112bb801\VH4\WindowsServices\GeneraPlanillaWindowsService\Salarios\Repository\GenericEntityRepository.cs:line 145
at Aseinfo.VH4.WindowsServices.Salarios.Ejecutores.EjecutorFormulacionBase.EjecutarGeneracion() in c:\BuildAgent\work\89066541112bb801\VH4\WindowsServices\GeneraPlanillaWindowsService\Salarios\Ejecutores\EjecutorFormulacionBase.cs:line 649
ClientConnectionId:a8e37580-1ce9-4300-b475-a20788f93cfc
Error Number:-2,State:0,Class:11