EX2019-CU10 OWA/ECP not working after July Security Update

Question

Hello,

After installing the July Security update access to ECP and OWA is broken.
Mail Flow works, but accessing OWA or ECP returns the following error:

ASSERT: HMACProvider.GetCertificates:protectionCertificates.Length<1

It also logs error 1003 to the Event Logs.

As many others have suggested, we have tried replacing the OATH Certificate according to this: https://learn.microsoft.com/en-us/exchange/troubleshoot/administration/cannot-access-owa-or-ecp-if-oauth-expired several times, we also waited >60 minutes after doing it - but the error persists. Even after full server reboot.

Please advice on what to do next.

Full Stack Trace Here:

Server Error in '/owa' Application.  
ASSERT: HMACProvider.GetCertificates:protectionCertificates.Length<1  
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: Microsoft.Exchange.Diagnostics.ExAssertException: ASSERT: HMACProvider.GetCertificates:protectionCertificates.Length<1  
  
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:  
  
  
[ExAssertException: ASSERT: HMACProvider.GetCertificates:protectionCertificates.Length<1]  
   Microsoft.Exchange.Diagnostics.ExAssert.AssertInternal(String formatString, Object[] parameters) +241  
   Microsoft.Exchange.Diagnostics.ExAssert.RetailAssert(Boolean condition, String formatString, T1 parameter1, T2 parameter2) +2694334  
   Microsoft.Exchange.Clients.Common.HmacProvider.GetCertificates() +363  
   Microsoft.Exchange.Clients.Common.HmacProvider.GetHmacProvider() +140  
   Microsoft.Exchange.Clients.Common.HmacProvider.ComputeHmac(Byte[][] messageArrays) +14  
   Microsoft.Exchange.HttpProxy.FbaModule.SetCadataCookies(HttpApplication httpApplication) +1032  
   Microsoft.Exchange.HttpProxy.FbaFormPostProxyRequestHandler.HandleFbaFormPost(BackEndServer backEndServer) +3581  
   Microsoft.Exchange.HttpProxy.FbaFormPostProxyRequestHandler.ShouldContinueProxy() +20  
   Microsoft.Exchange.HttpProxy.ProxyRequestHandler.BeginProxyRequestOrRecalculate() +257  
   Microsoft.Exchange.HttpProxy.ProxyRequestHandler.InternalOnCalculateTargetBackEndCompleted(TargetCalculationCallbackBeacon beacon) +1528  
   Microsoft.Exchange.HttpProxy.<>c__DisplayClass280_0.<OnCalculateTargetBackEndCompleted>b__0() +303  
   Microsoft.Exchange.Common.IL.ILUtil.DoTryFilterCatch(Action tryDelegate, Func`2 filterDelegate, Action`1 catchDelegate) +35  
   Microsoft.Exchange.HttpProxy.ProxyRequestHandler.CallThreadEntranceMethod(Action method) +59  
  
[AggregateException: One or more errors occurred.]  
   Microsoft.Exchange.HttpProxy.ProxyRequestHandler.EndProcessRequest(IAsyncResult result) +414  
   System.Web.CallHandlerExecutionStep.InvokeEndHandler(IAsyncResult ar) +231  
   System.Web.CallHandlerExecutionStep.OnAsyncHandlerCompletion(IAsyncResult ar) +172  
  
  
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4330.0   

Answer 1

Followed this instructions has solved the problem:
https://learn.microsoft.com/en-us/exchange/troubleshoot/administration/cannot-access-owa-or-ecp-if-oauth-expired

But is does take time (more then one hour) before it works.

Answer 2

Our Exchange does handle multiple SMTP-domains. The certificate was issued for the one marked default by Get-AcceptedDomain

Would I have to do this for all domains in the server?

Answer 3

Same problem here since Exchange security update last night. Recreating and assigning a new certificate will not resolve the problem.
Outlook works fine!, but OWA and ECP only work to signin page, after typing credentials it gives the message.

Hope someone can help to fix this!

Answer 4

We had this exact error from OWA/ECP and replacing the OAuth "Microsoft Exchange Server Auth Certificate" does work but the time for the certificate to "publish" seems to be inordinate. It was at least four hours for us, which happened to be over night so i'm not sure exactly how long.

To replace the OAuth cert, we followed these steps https://learn.microsoft.com/en-us/exchange/troubleshoot/administration/cannot-access-owa-or-ecp-if-oauth-expired with the exception of the domain being a wildcard, so -DomainName "*.contoso.com"

Answer 5

same error with CU9 and now with CU10.