Error While Uploading ExcelSheet

Question

Hi Im getting the  error  while im uploading the my Excel sheet, my code is working fine in local machine every time , but  in production some times it's  failing and giving the error, Once we restart the IIS server then it's sucessfully uploading. frequently we are facing this issues.

I gone through some solutions which are mentioned in some article like
<identity impersonate="false"/>

Still no luck....!



Error Description:

  System.Data.OleDb.OleDbException: Unspecified error at System.Data.OleDb.OleDbConnectionInternal..ctor(OleDbConnectionString constr, OleDbConnection connection) at System.Data.OleDb.OleDbConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup) at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) at System.Data.OleDb.OleDbConnection.Open() at System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataTable[] dataTables, Int32 startRecord, Int32 maxRecords, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataTable dataTable) at WebForms_frmPolicyIssuanceUpload.btnUpload_Click(Object sender, EventArgs e)