Dostałem ten wyjątek za pomocą SignalR, wdrożonego w Azure WebSites. Działa dobrze w środowisku debugowania. Jest to SignalR 1.0.1 i używam .NET MVC i WebApi

The data protection operation was unsuccessful. This may have been caused by not having the user profile loaded for the current thread's user context, which may be the case when the thread is impersonating.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.Security.Cryptography.CryptographicException: The data protection operation was unsuccessful. This may have been caused by not having the user profile loaded for the current thread's user context, which may be the case when the thread is impersonating.

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace: 
[CryptographicException: The data protection operation was unsuccessful. This may have     been caused by not having the user profile loaded for the current thread's user context, which may be the case when the thread is impersonating.]
Microsoft.Owin.Host.SystemWeb.<>c__DisplayClass1.<GetRethrowWithNoStackLossDelegate>b__0(Exception ex) +27
Microsoft.Owin.Host.SystemWeb.Utils.RethrowWithOriginalStack(Exception ex) +15
Microsoft.Owin.Host.SystemWeb.CallContextAsyncResult.End(IAsyncResult result) +47
Microsoft.Owin.Host.SystemWeb.OwinHttpHandler.EndProcessRequest(IAsyncResult result) +7
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9629708
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

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