Home > IT > OWA 2010: An unexpected error occurred and your request couldn’t be handled

OWA 2010: An unexpected error occurred and your request couldn’t be handled

Many of you might have encountered this error “An unexpected error occurred and your request couldn’t be handled” after applying Exchange 2010 SP1. This error will start showing up in OWA 2010 when you are trying to delete some messages or try to move them to another folders. So basically the Exchange it is fully functional but you can not delete any messages in OWA.

This error comes only after applying SP1 to the Exchange 2010.
There are many discussions on the web regarding this error and many solutions are also provided. Some of the people report this problem because of permissions on the folders or on the IIS directories, different permission sets on the IIS folders and so long.

You can find some of the discussions and solution in this links below:



Some of the posts blame Authentication method or even editing the web.config file and altering some of the values in there in order to make it work.

You might also get an Event Error in the event log like :

Event ID:      3
The service ‘/EWS/Exchange.asmx’ cannot be activated due to an exception during compilation.


Event ID:      108
Outlook Web App couldn’t connect Exchange Web Services due to a configuration error.

For me none of this solutions applied.

I was fighting with this error for a few good hours then I decided that I am stupid and I made some mistake somewhere that it was impossible to detect. And since this was a newly installed server and admins with real balls never take backups of newly installed machines I decided to re-install.

After re-installing the machine, I configured the Exchange, assured that everything works as intended and re-installed SP1. SAME ERROR !

After looking at the log files and all this articles one more time (a few hours later) it hit me. What could I have changed at the Exchange (the IIS part that is) to provoke the error.
Then it hit me.
The ONLY thing I changed in my IIS configuration was my HOST HEADERS on my default website.
Went to IIS, removed ANY host headers I had there and then everything WORKED.

So for all you out there, if you have this kind of error, first thing you want to try is to take a look at your host headers and remove any custom host headers then try all the other solutions.

  1. theogray
    April 27, 2012 at 10:00 am

    Thanks for this, removing the host header solved the problem straight away!

  2. Arun
    September 21, 2012 at 3:26 pm

    Simply a reboot of the server fixed the issue for me…

  3. Don Scott
    November 8, 2012 at 4:26 pm

    Thanks for this, cured the problem in one go!

  4. Phil
    February 5, 2014 at 4:52 pm

    Thanks, I ran into this problem and never would have though it was due to host headers.

  5. April 4, 2014 at 3:31 pm

    Posting my fix for others… In my case I fixed this by changing the ‘.Net CLR Version’ of the MSExchangePowershellAppPool from version 4 to version 2.

    I too struggled for hours on this one, on no other site have I seen mention of what worked for me, I hope it helps…

  1. March 6, 2012 at 8:33 am

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