Workflows do not progress on task completion

I have a situation whereby there was intermittent connectivity issues between SharePoint and WFM for a few weeks. The issue is now resolved however during this time, workflow tasks that were generated got approved. However due to the connection problem, the task completions couldn't communicate back to Workflow Manager to let it know to move to the next step. Therefore in the workflow status page, the task is completed however the next step which is to generate the next task, doesn't happen. There is no error message in the workflow status. 

The SharePoint ULS Logs reported this error at the point in time when the task was approved (during the connection issue period). 

Is there any way I can get SharePoint to tell Workflow Manager that the task is completed and that it can move on to the next step??

Microsoft.Workflow.Client.WorkflowEndpointNotFoundException: Unable to connect to the remote service at http://<wfm server>12291/SharePoint/default/90fb830b-8964-4067-84be-526daaf85068/bc1d262e-bccc-4ef2-a69f-347ece571310/$Notifications?$expectedScopeRevision=0. See InnerException for more details. Client ActivityId : d105799d-1459-4079-7a09-fdfc061394c5. ---> System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it 10.56.100.163:12291

at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)

at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Exception& exception) -

-- End of inner exception stack trace ---

at Microsoft.Workflow.Common.AsyncResult.End[TAsyncResult](IAsyncResult result)

at Microsoft.Workflow.Client.HttpGetResponseAsyncResult`1.End(IAsyncResult result)

at Microsoft.Workflow.Client.ClientHelpers.SendRequest[T](HttpWebRequest request, T content) -

-- End of inner exception stack trace ---

at Microsoft.Workflow.Client.ClientHelpers.SendRequest[T](HttpWebRequest request, T content)

at Microsoft.Workflow.Client.HttpWorkflowNotificationPublisher.OnPublishNotification(String address, WorkflowNotification notification, ICredentials credentials, String userCulture, Guid traceActivityId, TimeSpan requestTimeout)

at Microsoft.Workflow.Client.WorkflowNotificationPublisher.PublishNotification(String address, WorkflowNotification notification, ICredentials credentials, String userCulture, Guid traceActivityId, TimeSpan requestTimeout)

at Microsoft.Workflow.Client.WorkflowManagementClient.PublishNotification(WorkflowNotification notification, IDictionary`2 activationMetadata, Int64 expectedScopeRevision)

at Microsoft.SharePoint.WorkflowServices.WorkflowProxy.PublishEvent(String eventSource, String eventType, IDictionary`2 payload, SPUserToken userToken) StackTrace:

at Microsoft.Office.Server.Native.dll: (sig=a1000fac-02c7-4003-8d43-320bb54966b7|2|microsoft.office.server.native.pdb, offset=131D6)

at Microsoft.Office.Server.Native.dll: (offset=21B79)