OWA and ECP doesn't work after update KB5004780

Marc Meul 11 Reputation points


After installing the update KB5004780 OWA and ECP doesn't work anymore.

The error in the eventviewer doesn't give me enough information.
I can't find anything useful online about the error message.

Anyone else out there with something similar or a better solution?

Kind regards,

Process information:
Process ID: 2064
Process name: w3wp.exe

Exception information:
Exception type: ExAssertException
Exception message: ASSERT: HMACProvider.GetCertificates:protectionCertificates.Length<1
at Microsoft.Exchange.Diagnostics.ExAssert.AssertInternal(String formatString, Object[] parameters)
at Microsoft.Exchange.Diagnostics.ExAssert.RetailAssert[T1,T2](Boolean condition, String formatString, T1 parameter1, T2 parameter2)
at Microsoft.Exchange.Clients.Common.HmacProvider.GetCertificates()
at Microsoft.Exchange.Clients.Common.HmacProvider.GetHmacProvider()
at Microsoft.Exchange.Clients.Common.HmacProvider.ComputeHmac(Byte[][] messageArrays)
at Microsoft.Exchange.HttpProxy.FbaModule.SetCadataCookies(HttpApplication httpApplication)
at Microsoft.Exchange.HttpProxy.FbaFormPostProxyRequestHandler.HandleFbaFormPost(BackEndServer backEndServer)
at Microsoft.Exchange.HttpProxy.FbaFormPostProxyRequestHandler.ShouldContinueProxy()
at Microsoft.Exchange.HttpProxy.ProxyRequestHandler.BeginProxyRequestOrRecalculate()
at Microsoft.Exchange.HttpProxy.ProxyRequestHandler.InternalOnCalculateTargetBackEndCompleted(TargetCalculationCallbackBeacon beacon)
at Microsoft.Exchange.HttpProxy.ProxyRequestHandler.<>c__DisplayClass280_0.<OnCalculateTargetBackEndCompleted>b__0()
at Microsoft.Exchange.Common.IL.ILUtil.DoTryFilterCatch(Action tryDelegate, Func2 filterDelegate, Action1 catchDelegate)
at Microsoft.Exchange.HttpProxy.ProxyRequestHandler.CallThreadEntranceMethod(Action method)

Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Marc Meul 11 Reputation points

    Hi @Yuki Sun-MSFT ,

    Thanks for your response, I've already tried that but with no luck.
    Maybe I didn't wait long enough. I will try again.

    For now uninstalling the patch did the job; but that is not a real solution. But ECP and OWA works again.

    Thanks for the link; I will follow that thread to.

    Many people suffer from it. This is also an interesting link

    1 person found this answer helpful.

  2. Yuki Sun-MSFT 40,781 Reputation points

    Hi @Marc Meul

    Please follow the steps in the article below to re-publish the Oauth certificate, then wait for a few hours for the change to take place:
    Can't sign in to Outlook on the web or EAC if Exchange Server OAuth certificate is expired

    Here's a similar case for reference: Exchange Server error in '/owa' application.

    If an Answer is helpful, please click "Accept Answer" and upvote it.
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  3. 2021-08-02T03:29:12.313+00:00

    The fix suggested is definitely working. Please be patient grab a coffee and check back later. I had to give it 3 hours for it to work.

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  4. alex a 61 Reputation points

    Works for me too.
    Take 2h and a half for me (i have no more hairs...)

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  5. alex a 61 Reputation points

    Worked for me too and take 2 hours and half

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