Exchnage 2013 ECP and OWA error

Rob Andrews 1 Reputation point

Hi All

I have been updating our exchange server with all the windows updates so I can run the CU23 update,

I have temp done the iis rewrite rules advised and stopped all external 443 access whilst we patch the server BUT

I can no longer get in to ECP or OWA, PowerShell works ok as long as I run as admin.

I get am error when going to OWA from the server or ECP from the server

Server error in /owa application

The length of the query string for this request exceeds the configuration maxquuerystringlenghth value

I am currently on exchange 2013 CU18 running on a Server 2012R2 server with all the updates run

I dont want to try run the CU23 update in case it kills exchange due to this error above but need to do this so we can migrate the exchange to Office 365

any ideas please

Thanks in advance

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. Rob Andrews 1 Reputation point

    No it’s not the rules as it was working after I applied them started after I did a round of server updates. Unfortunately there where a few security updates for exchange and 2012 so not sure which one killed it

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  2. Andy David - MVP 110.4K Reputation points Microsoft MVP

    Well, I think the other way around :)

    I would be applying .net 4.8, then CU23 then the patch and see if it it works after that since this a .net issue
    If not, then setting the manual values in the web.config:

    Get a full backup of Exchange

    Just FYI, be sure to follow these steps to go from Cu18 to Cu23, rebooting after EACH step and running from an ELEVATED PROMPT.


    Run each step separately:
    Setup.exe /IAcceptExchangeServerLicenseTerms /PrepareSchema
    Setup.exe /IAcceptExchangeServerLicenseTerms /PrepareAD
    Setup.exe /IAcceptExchangeServerLicenseTerms /PrepareAllDomains

    Install .net 4.8

    Then install CU23:


    Then install the security patch:

    Critical Patch:

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  3. Rob Andrews 1 Reputation point

    thanks I will try this on our VM backup first, I have tried recreating the front end and backend virtual directories with no success
    I think this error started after i updated .net to 4.7.2
    with over 100 users i need to be partly confidant it wont kill exchange completely


  4. Rob Andrews 1 Reputation point

    thanks did not see that and thought updating it to 4.7.2 in advance would have been enough.
    done the upgrade to cu23 on our backup VM Host and after 6 hours of some errors i had to manually overcome it finally did it and allows me in to exchange, will try it for real now .

    thanks for your input and fingers crossed

  5. The Network Company 116 Reputation points

    Also helpful might be to run dpaulson45's heathchecker.ps1 script or the tasks it performs. It can help expose version issues with .Net and the VC runtimes as well as misconfigured host settings and general Exchange health issues.

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