Anonymous Calendar Sharing URL in Exchange is not working between Exchange 2016/2019 coexistence

Evandro Boa Semedo 366 Reputation points
2021-10-22T21:14:58.713+00:00

Hi guys,

(Scenery)

I have 4 Exchange Servers 2016 CU22 Frontend; Only CAS Function | CAS Role

I have 6 Exchange Servers 2019 CU11 Backend; Only MBX Function | MBX Role

(Flow)

Internet ==> HLB (Hardware Load Balancer) ==> CAS ==> MBX

PS: Exchange Server 2016 CU22 is kept as CAS Role to maintain compatibility with older email clients.
PS: I applied the Security Updates for both versions as well, but I tried it before without applying it and it didn't work either.

All users when accessing shared calendar settings get this error <HTTP ERROR 500> below using Exchange Server 2016 CU22 with proxy function.

144476-143025-print-1.png

But. if i access directly through an Exchange Server 2019 CU11 using my file host by VPN to test the feature works perfectly.

144477-143101-print-2.png

Follow the configuration:

143054-print-3.png

143055-print-4.png

Source: https://techcommunity.microsoft.com/t5/exchange-team-blog/how-to-publish-anonymous-calendar-sharing-url-in-exchange-online/ba-p/586924

Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
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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.
7,284 questions
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Accepted answer
  1. Evandro Boa Semedo 366 Reputation points
    2021-10-28T20:56:57.087+00:00

    There is a bug in url rewrite, somehow it's not being imported correctly causing some code failure. If you create any rule that is, invalid or valid and apply it, it will work again. If you delete the rule, however invalid it may be, it also works again, as the web.config structure ends up being corrected in some way.

    C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy\owa\web.config

    vDIR Export Rules

    cd "C:\Windows\System32\inetsrv"
    appcmd list config "Default Web Site/owa" -section:system.webServer/rewrite/rules -xml > P:\owarewriterules13-10-2021.xml

    vDIR Import Rules

    cd "C:\Windows\System32\inetsrv"
    appcmd set config "Default Web Site/owa" -in < P:\owarewriterules13-10-2021.xml

    I can say that I managed to solve my problem this way, because the failure was in the structure of the web.config imported from the backup xml by the cmd prompt itself.

    But, looks like a bug.

    1 person found this answer helpful.

12 additional answers

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  1. Andy David - MVP 139.8K Reputation points MVP
    2021-10-25T13:15:49.37+00:00

    This doesnt make sense honestly:
    Internet ==> HLB (Hardware Load Balancer) ==> CAS ==> MBX

    Also, there is no such thing as a CAS or MBX only role in 2016/2019

    "Exchange Server 2016 CU22 is kept as CAS Role to maintain compatibility with older email clients" Which clients are these?

    Both the 2016 and 2019 server should be in the load balancer with all the same URLs for all the client virtual directories


  2. Andy David - MVP 139.8K Reputation points MVP
    2021-10-25T13:47:52.433+00:00

    Well, Outlook 2007 isnt supported for Exch 2016 neither :)

    https://learn.microsoft.com/en-us/exchange/plan-and-deploy/supportability-matrix?view=exchserver-2019#clients

    Are you sure this isnt a load balancer or firewall issue?


  3. Andy David - MVP 139.8K Reputation points MVP
    2021-10-25T15:41:20.763+00:00

    Did you enable the correct settings on the 2016 server?
    https://learn.microsoft.com/en-us/exchange/create-a-sharing-policy-exchange-2013-help

    143533-image.png


  4. Andy David - MVP 139.8K Reputation points MVP
    2021-10-25T19:34:09.747+00:00

    Anything interesting in the proxy logs on the 2016 server?

    C:\Program Files\Microsoft\Exchange Server\V15\Logging\HttpProxy

    or in the event logs?

    Another thought: Is TLS 1.2 enforced on the 2016 server? ( It will be on 2019)