It doesn't happen often, but sometimes Courier will not deploy a PDF. None of the files on our site are greater than 15MB.

Here's the error in the logs:

2019-01-11 10:10:26,647 [141] INFO Umbraco.Courier.Core.TaskManager - [Thread 141] Starting ExtractionTask with id: f742fe2a-a6b8-4dd2-a585-5b24adfc1ad6 2019-01-11 10:10:26,647 [141] INFO Umbraco.Courier.Core.Tasks.ExtractionTask - [Thread 141] ExtractionTask running by user XXXXXXXXXX 2019-01-11 10:10:26,647 [141] INFO Umbraco.Courier.Core.Extraction.RevisionExtraction - [Thread 141] Running PopulateGraph 2019-01-11 10:10:26,662 [141] INFO Umbraco.Courier.Core.Extraction.RevisionExtraction - [Thread 141] Finished PopulateGraph (took 22ms) 2019-01-11 10:10:26,662 [141] INFO Umbraco.Courier.Core.Extraction.RevisionExtraction - [Thread 141] Starting extraction 2019-01-11 10:10:26,662 [141] INFO Umbraco.Courier.Core.Extraction.RevisionExtraction - [Thread 141] Opens database session 2019-01-11 10:10:26,678 [141] INFO Umbraco.Courier.Core.Extraction.RevisionExtraction - [Thread 141] Transfering pre-extraction files 2019-01-11 10:10:27,397 [141] DEBUG Umbraco.Courier.Persistence.V6.NHibernate.NHibernateProvider - [Thread 141] Closing session, UseGlobalSession: False, key: 7cc0d69c-fb64-4814-9a0f-5c1436314e23 2019-01-11 10:10:27,412 [141] ERROR Umbraco.Courier.Core.TaskManager - [Thread 141] Error ExtractionTask with id: f742fe2a-a6b8-4dd2-a585-5b24adfc1ad6 System.Net.WebException: The request failed with HTTP status 404: Not Found. at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at Umbraco.Courier.RepositoryProviders.WebServiceProvider.RepositoryWebservice.TransferResources(String sessionKey, ResourceTransfer[] resources) at Umbraco.Courier.Core.Extraction.RevisionExtraction.TransferItemResources(Item item, ResourceExtractionOrder order) at Umbraco.Courier.Core.Extraction.RevisionExtraction.TransferPreExtractResource() at Umbraco.Courier.Core.Extraction.RevisionExtraction.Extract() at Umbraco.Courier.Core.Tasks.ExtractionTask.Run() at Umbraco.Courier.Core.BackgroundTaskRunner1.ConsumeTaskInternal(T task) 2019-01-11 10:10:27,412 [141] ERROR Umbraco.Courier.Core.BackgroundTaskRunner - [Thread 141] An error occurred consuming task System.Net.WebException: The request failed with HTTP status 404: Not Found. at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at Umbraco.Courier.RepositoryProviders.WebServiceProvider.RepositoryWebservice.TransferResources(String sessionKey, ResourceTransfer[] resources) at Umbraco.Courier.Core.Extraction.RevisionExtraction.TransferItemResources(Item item, ResourceExtractionOrder order) at Umbraco.Courier.Core.Extraction.RevisionExtraction.TransferPreExtractResource() at Umbraco.Courier.Core.Extraction.RevisionExtraction.Extract() at Umbraco.Courier.Core.Tasks.ExtractionTask.Run() at Umbraco.Courier.Core.BackgroundTaskRunner1.ConsumeTaskInternal(T task)

Umbraco version: 7.10.4 (with security patch installed) Courier version: 3.1.6

Any suggestions would be helpful.