Exchange 2010 EWS - app_global.asax-error.

Question

Im setting up an Exchange Online deployment on a costumers server enviroment. They have a single Exchange 2010 SP3 with Rollup 6 installed.
The users started complaining that they couldnt set out-of-office messages in Outlook, and that they were prompted for Exchange password in Lync repeatedly.
Now, im not sure if these errors came because of the Hybrid setup of its a coincidence, but here is what Ive done:
I started the Hybrid Wizard, but this one got some errors, so it didnt complete on the first run. The error was the following:
http://support.microsoft.com/kb/2626696
and I ran
ServiceModelReg.exe –r
on the server to fix it. This solved this problem, but a new one occurred with publishing of Autodiscover and EWS online. I called it a day, and was busy the next day so this was left like this for a few days.
The next day a few users complained that they couldnt set out of office. The next day after that, the lync error occured (there was a reboot that night. Im not sure if thats relevat). The errors in the Hybrid-wizard had then been solved, and the Hybrid-wizard
ran through, but the EWS-problem remained. 
Now, on the server I get this error every second or so:
+
System
Provider
[ Name]
System.ServiceModel 3.0.0.0
EventID
3
[ Qualifiers]
49154
Level
2
Task
5
Keywords
0x80000000000000
TimeCreated
[ SystemTime]
2014-09-25T15:36:32.000000000Z
EventRecordID
933734
Channel
Application
Computer
<Server Name>
Security
[ UserID]
S-1-5-18
EventData
System.ServiceModel.ServiceHostingEnvironment+HostingManager/20974680
System.ServiceModel.ServiceActivationException: The service '/EWS/Exchange.asmx' cannot be activated due to an exception during compilation. The exception message is: Could not load file or assembly 'App_global.asax.hid_mutt,
Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.. ---> System.IO.FileNotFoundException: Could not load file or assembly 'App_global.asax.hid_mutt, Version=0.0.0.0, Culture=neutral,
PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified. File name: 'App_global.asax.hid_mutt, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' at System.Reflection.Assembly._nLoad(AssemblyName fileName, String codeBase,
Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection) at System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark,
Boolean forIntrospection) at System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) at System.Reflection.Assembly.Load(String assemblyString) at System.ServiceModel.Activation.ServiceHostFactory.CreateServiceHost(String
constructorString, Uri[] baseAddresses) at System.ServiceModel.ServiceHostingEnvironment.HostingManager.CreateService(String normalizedVirtualPath) at System.ServiceModel.ServiceHostingEnvironment.HostingManager.ActivateService(String normalizedVirtualPath)
at System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath) WRN: Assembly binding logging is turned OFF. To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog]
(DWORD) to 1. Note: There is some performance penalty associated with assembly bind failure logging. To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog]. --- End of inner exception stack trace --- at System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvailable(String
normalizedVirtualPath) at System.ServiceModel.ServiceHostingEnvironment.EnsureServiceAvailableFast(String relativeVirtualPath)
w3wp
4440
Any ideas is appreciated. 

Answer 1

Hi,
I am glad to hear that issue solved by yourself.
Event 3 indicated that Exchange missed Anonymous authentication on autodiscover/EWS Virtual directories.
To solve this issue, please enable Anonymous authentication on autodiscover/EWS Virtual directories through IIS manager by the following steps:
Open IIS manager.
Navigate to Sites>Default Web Site>Autodiscover.
Refer to the following picture to choose Authentication, then double-click it. Try to enable Anonymous Authentication.
Repeat steps 1-3 to enable Anonymous authentication on EWS.
Best Regards.