title: Umbraco: An unexpected network error on Azure Web Apps
body: <p>We have an Umbraco website (version 7.5.11) hosted on Azure Web Apps.</p>
  
  <p>We are experiencing the following exception intermittently (3 times within the past 3 weeks). Once the exception occurs it brings the website down until we republish the home node in Umbraco. At all other times the website is working as expected, including retrieving image files from the server.</p>
  
  <p><em>Exception type: IOException</em></p>
  
  <p><em>Exception message: An unexpected network error occurred. at Umbraco.Core.Cache.HttpRuntimeCacheProvider.GetCacheItem(String cacheKey, Func1 getCacheItem, Nullable1 timeout, Boolean isSliding, CacheItemPriority priority, CacheItemRemovedCallback removedCallback, CacheDependency dependency) at Umbraco.Core.Cache.HttpRuntimeCacheProvider.GetCacheItem(String cacheKey, Func1 getCacheItem, Nullable1 timeout, Boolean isSliding, CacheItemPriority priority, CacheItemRemovedCallback removedCallback, String[] dependentFiles) at Umbraco.Core.Cache.DeepCloneRuntimeCacheProvider.GetCacheItem(String cacheKey, Func1 getCacheItem, Nullable1 timeout, Boolean isSliding, CacheItemPriority priority, CacheItemRemovedCallback removedCallback, String[] dependentFiles) at Umbraco.Web.PublishedCache.XmlPublishedCache.PublishedMediaCache.GetCacheValues(Int32 id, Func2 func) at Umbraco.Web.PublishedCache.XmlPublishedCache.PublishedMediaCache.GetUmbracoMedia(Int32 id) at Umbraco.Web.PublishedCache.XmlPublishedCache.PublishedMediaCache.GetById(UmbracoContext umbracoContext, Boolean preview, Int32 nodeId) at Umbraco.Web.PublishedCache.ContextualPublishedCache1.GetById(Boolean preview, Int32 contentId) at Umbraco.Web.PublishedContentQuery.DocumentById(Int32 id, ContextualPublishedCache cache, Object ifNotFound) at Umbraco.Web.PublishedContentQuery.Media(Int32 id) at Umbraco.Web.UmbracoHelper.Media(String id)</em> </p>
  
  <p>The media file exists, and republishing the home node brought the site back online.</p>
  
  <p>At the time of the exception, no code changes were deployed and no pages were updated / published within Umbraco.</p>
  
  <p>Has anyone experienced something similar, or any ideas what the root cause is?</p>