Media library images not displaying - Invalid URI: The URI is empty

Question

I'm on Sitecore 9.0. Sporadically after a build, the Media Library images all display as broken and when I try to browse to an image directly (e.g. mysite.com/-/media/images/logo.png) I see a server error:

[UriFormatException: Invalid URI: The URI is empty.]
System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind) +261
Sitecore.Xdb.ReferenceData.Client.ReadOnlyReferenceDataHttpClient.get_ServiceAddressFromConnectionString() +110
Sitecore.Xdb.ReferenceData.Client.ReferenceDataHttpClient..ctor(IDefinitionEnvelopeConverter definitionConverter, IEnumerable`1 clientModifiers, IEnumerable`1 webRequestHandlerModifiers, ILogger`1 logger) +25

[TargetInvocationException: Exception has been thrown by the target of an invocation.]
System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) +0
System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +217
Sitecore.Reflection.ReflectionUtil.CreateObject(Type type, Object[] parameters) +119
Sitecore.Configuration.DefaultFactory.CreateFromTypeName(XmlNode configNode, String[] parameters, Boolean assert) +108
Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper) +163
Sitecore.Configuration.DefaultFactory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert) +72
Sitecore.Configuration.DefaultFactory.CreateObject(String configPath, String[] parameters, Boolean assert) +697
Sitecore.Xdb.ReferenceData.Client.Xmgmt.c.b__0_0(IServiceProvider provider) +41
lambda_method(Closure , ServiceProvider ) +19327
Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetService(IServiceProvider provider) +61
Sitecore.Marketing.Definitions.DefinitionManagerFactory.GetDefinitionManager() +84
Sitecore.Analytics.Data.c__DisplayClass7_0.b__4() +69
System.Lazy`1.CreateValue() +708
System.Lazy`1.LazyInitValue() +184
Sitecore.Analytics.Data.MarketingDefinitions.InitializeProfilesWithDefaultValues() +80
System.Lazy`1.CreateValue() +708
System.Lazy`1.LazyInitValue() +184
Sitecore.Analytics.Data.TrackingField.InitializeProfiles() +106
Sitecore.Analytics.Data.TrackingField..ctor(Field innerField) +133
Sitecore.Analytics.Data.TrackingField.GetTrackingField(Item item) +106
Sitecore.Analytics.Data.TrackingField.FindTrackingField(Item item) +37
Sitecore.Analytics.Data.TrackingField.HasTracking(Item item) +9
Sitecore.Analytics.Media.MediaRequestTrackingInformation.IsTrackedRequest() +38
Sitecore.Analytics.RobotDetection.Media.MediaRequestSessionModule.IsSessionRequired() +162
Sitecore.Analytics.Media.MediaRequestSessionModule.ContextPostMapRequestHandler(Object sender, EventArgs e) +17
System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +223
System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +213
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +91

Sometimes recycling the app pool resolves this but I want to understand what's causing this issue and the best way to resolve it.

Answer 1

The issue was that xdb was enabled but not configured; Xdb.Enabled and Xdb.Tracking.Enabled were set to true but there was not connectionstring for xdb (which is what was reporting the empty URI). Disabled Xdb and that fixed the issue