Often, your server can only access the internet through a proxy server. If that's the case, make sure your proxy server is listed in the web.config so the HttpClient used by Sentry's SDK can pick it up.

      <proxy proxyaddress="" bypassonlocal="true" />

If you're not able to capture events from ASP.NET to Sentry on older versions of Windows Server, with the older .NET Framework, you must enable TLS 1.2.

using System.Net;

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12

If you get the following error during Sentry initialization, you may have a misconfiguration on your Web.config:

System.IO.FileNotFoundException: Could not load file or assembly System.Net.Http, Version=

You can fix it with one of the three solutions below:

  • Find the assemblyIdentity for System.Net.Http and remove the bindingRedirect.
  <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
  • Find the assemblyIdentity for System.Net.Http and lower the newVersion to
  <assemblyIdentity name="System.Net.Http" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
  <bindingRedirect oldVersion="" newVersion="" />
  • Install the latest package from System.Net.Http in NuGet into your project.

You can find more information about the problem in this GitHub issue.

This happens because the scope from requests will be different from the one executed during the execution of Application_Start. To apply Tags globally, it's recommended that you set them in SentryOptions, as shown in the example below:

SentrySdk.Init(options =>
  options.Dsn = "";
  options.DefaultTags.Add("TagName", "value");

The call is ambiguous between the following methods or properties:
and Sentry.SentryOptionsDiagnosticExtensions.DisableDiagnosticSourceIntegration(Sentry.SentryOptions)

The above error means that the version of the Sentry package you are using already contains the DiagnosticSource integration within itself, but you additionally installed Sentry.DiagnosticSource, which is only relevant for older framework versions.

To resolve this problem, remove the package reference to Sentry.DiagnosticSource.

SentryOptions does not contain a definition for AddDiagnosticSourceIntegration.

The above error could have two meanings:

  • You're using an outdated SDK (3.8.3 or older).

  • Your project already includes the integration automatically. You can validate it by observing the debug information from Sentry SDK. Enable it through the options.

Your debug window will have following messages:

Debug: Logging enabled with ConsoleDiagnosticLogger and min level: Debug
Debug: Initializing Hub for Dsn: ''.
Debug: Using 'GzipBufferedRequestBodyHandler' body compression strategy with level Optimal.
Debug: New scope pushed.
Debug: Registering integration: 'AutoSessionTrackingIntegration'.
Debug: Registering integration: 'AppDomainUnhandledExceptionIntegration'.
Debug: Registering integration: 'AppDomainProcessExitIntegration'.
Debug: Registering integration: 'TaskUnobservedTaskExceptionIntegration'.
Debug: Registering integration: 'SentryDiagnosticListenerIntegration'.

If the debug file contains information about SentryDiagnosticListenerIntegration, then your project already includes the integration automatically.

From version 3.14.0, Sentry will respect Implicit Usings. This means is Implicit Usings is enabled (<ImplicitUsings>enable</ImplicitUsings> or <ImplicitUsings>true</ImplicitUsings>) then Sentry will be added to the current global using directives. This means that using Sentry; can be omitted from any .cs files.

In some scenarios Implicit Usings can result in type name conflicts. For example Session may exist in multiple namespaces. This can be resolved by fully qualifying the type inline (Sentry.Session), or with a using alias:

using SentrySession = Sentry.Session;

Then SentrySession can be used instead of Sentry.Session.

Help improve this content
Our documentation is open source and available on GitHub. Your contributions are welcome, whether fixing a typo (drat!) or suggesting an update ("yeah, this would be better").