Hello,

We use: Umbraco version 7.1.8 - Newsletter Studio v2.1.4

Sometimes (it is not a consistent error) when we try to send a newsletter we get the following error during the initialization of newsletter sending.

When this error occurs none of newsletter emails are being send to mailing list receivers.

Can you help us please?

2019-04-15 13:15:35,691 [9] INFO umbraco.BusinessLogic.Log - [Thread 34] Redirected log call (please use Umbraco.Core.Logging.LogHelper instead of umbraco.BusinessLogic.Log) | Type: Error | User: 0 | NodeId: 0 | Comment: NewsletterStudio, SendNewsletterService: Invalid operation. The connection is closed. : at System.Data.ProviderBase.DbConnectionClosed.CreateReferenceCollection() at System.Data.ProviderBase.DbConnectionInternal.AddWeakReference(Object value, Int32 tag) at System.Data.SqlClient.SqlConnection.AddWeakReference(Object value, Int32 tag) at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString, Boolean isInternal, Boolean forDescribeParameterEncryption) at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, Boolean inRetry, SqlDataReader ds, Boolean describeParameterEncryptionRequest) at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean& usedCache, Boolean asyncWrite, Boolean inRetry) at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method) at System.Data.SqlClient.SqlCommand.ExecuteScalar() at NewsletterStudio.Infrastucture.Data.PetaPoco.Database.Insert(String tableName, String primaryKeyName, Boolean autoIncrement, Object poco) at NewsletterStudio.Infrastucture.Data.PPDatabaseAdaptor.Insert(String tableName, String primaryKeyName, Object obj) at NewsletterStudio.Infrastucture.Data.EmailTrackingItemRepository.Save(EmailTrackingItem emailTrackingItem) at NewsletterStudio.Services.EmailTrackingItemService.CreateTrackingItems() at NewsletterStudio.Services.SendNewsletterService.SendEmails()