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

Question

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.

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

Follow the configuration:

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

Answer 1

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.

Answer 2

Ok, you cant enforce TLS 1.2 if you are using those older clients unfortunately

The logs you have there only show healthMailboces.
How about the failures? Do you see those - check the EWS proxy logs as well.

Answer 3

@Andy David - MVP ,

I isolated an Exchange Server 2016 Frontend (Example SRVCAS001) to use only TLS 1.2. Only I am accessing this front end server.

2021-10-26T14:43:17.630Z,1eb4ef7b-1dfd-481b-8cf6-ddfebfbbb91e,15,2,986,9,Unknown,skysfb001/16074dce-4675-4419-856a-aac1152e3fed/[4201777466],Bearer,true,evandro****.br,*.br,LYNC/6.0.9319.534/Storage,Target=None;Req=Exchange2013/Exchange2013;,192.168.***SRV007,CAS001.****.BR,GetImItemList,200,883,,,evandro.*.br,,,67edec1a0be5444faadab692b9265cf6,0f90c229-94d8-46fc-b443-defac3c20e1e,PrimaryServer,LocalTask,0,0,0,0,0,,,,,,,,,,,,,,,,,,,,[C],0,0,17,18,3,,9,5,,66,86,24,111,,,SKU=Unknown;App_BeginReq_Start=0;App_BeginReq_End=0;GetHandler_Start=1;RequestHandler=Wcf;GetHandler_End=2;BackEndAuthenticator=OAuthAuthenticator;TotalBERehydrationModuleLatency=0;SkipMailboxRead=False;ADIdentityCache=Miss;AuthzFlags=AuthzSkipTokenGroups;CSCMissLatency=1;SkipMailboxRead=False;AuthzFlags=AuthzSkipTokenGroups;CSCMissLatency=2;CARB=1;ImGroupCount=6;PersonaCount=4;ContactCount=5;cpn=RUM_ABR/RUM_ABRC/ABR/APAR/EWS_CE/EWS_CEC/APSRH/APRHE/RUM_AER/RUM_AERC/AER/AERC/;cpv=0/0/0/1/86/110/111/111/111/111/111/111/;MailboxTypeCacheSize=427815;S:AspDispatchLatency.BeginRequest=0;S:ADRS.InclI=1;S:AspDispatchLatency.EndRequest=0;S:ADRS.Check=00;S:ServiceTaskMetadata.WatsonReportCount=0;S:WLM.Bal=299964.2;S:ServiceTaskMetadata.ServiceCommandBegin=86;S:ServiceTaskMetadata.ServiceCommandEnd=110;S:ActivityStandardMetadata.Component=Ews;S:WLM.BT=Ews;S:EwsMetadata.HttpHandlerGetterLatency=0;Dbl:WLM.TS=111;Dbl:CCpu.T[CMD]=15.625;I32:ADR.C[DC003]=1;F:ADR.ALDC003]=1.6082;I32:ADS.CDC003]=1;F:ADS.AL[DC003]=3.547;I32:ATE.C[DC004.****.br]=1;F:ATE.AL[DC004***.br]=0;Dbl:BudgUse.T[]=23.8950996398926;I32:ATE.C[DC003..br]=2;F:ATE.AL[DC003..br]=30;Dbl:MAPI.T[SRV007.bb0ca4b9-b87d-4bf9-9451-da291c193021]=19;I32:ADR.C[DC001]=1;F:ADR.AL[DC001]=1.5382;I32:MAPI.C[SRV007.bb0ca4b9-b87d-4bf9-9451-da291c193021]=51;I32:ROP.C[SRV007.bb0ca4b9-b87d-4bf9-9451-da291c193021]=734443387;Dbl:RPC.T[SKYSRV007.bb0ca4b9-b87d-4bf9-9451-da291c193021]=19;I32:RPC.C[SRV007.bb0ca4b9-b87d-4bf9-9451-da291c193021]=17;I32:ATE.C[DC001..br]=1;F:ATE.AL[DC001..br]=0;Dbl:VCGS.T[SKYSRV007]=0;I32:VCGS.C[SRV007]=2;Dbl:EXR.T[SRV007.bb0ca4b9-b87d-4bf9-9451-da291c193021]=8;Dbl:ST.T[SRV007.bb0ca4b9-b87d-4bf9-9451-da291c193021]=4;I32:MB.C[SRV007.bb0ca4b9-b87d-4bf9-9451-da291c193021]=17;F:MB.AL[SRV007.bb0ca4b9-b87d-4bf9-9451-da291c193021]=1.117647;I32:ADS.C[DC004]=1;F:ADS.AL[DC004]=2.5858,,,,2021-10-26T14:43:17.511Z,15432,,644263248,652711840,564906_71837_2978,564907_71837_2978,,,,,,,,,,,,

My mailbox is hosted on Exchange Mailbox 2019 backend using only TLS 1.2.

C:\Program Files\Microsoft\Exchange Server\V15\Logging\HttpProxy\Owa #No errors found
C:\Program Files\Microsoft\Exchange Server\V15\Logging\HttpProxy\OwaCalendar #No errors found
C:\Program Files\Microsoft\Exchange Server\V15\Logging\Ews #No errors found
C:\Program Files\Microsoft\Exchange Server\V15\Logging\HttpProxy\Ews #No errors found
C:\Program Files\Microsoft\Exchange Server\V15\Logging\OWAAnonymous #No errors found
C:\Program Files\Microsoft\Exchange Server\V15\Logging\CalendarAssistantsLogs #No errors found
C:\Program Files\Microsoft\Exchange Server\V15\Logging\Calendar Repair Assistant #No errors found

Outlook event logs:

O Outlook carregou o(s) seguinte(s) suplemento(s):

Nome: Microsoft Exchange Add-in
Descrição: Exchange support for Unified Messaging, e-mail permission rules, and calendar availability.
ProgID: UmOutlookAddin.FormRegionAddin
GUID: {F959DBBB-3867-41F2-8E5F-3B8BEFAA81B3}
Comportamento do Carregamento: 3
HKLM: 1
Local: C:\Program Files\Microsoft Office\root\Office16\ADDINS\UmOutlookAddin.dll
Tempo de Inicialização (milissegundos): 16

Nome: Microsoft Teams Meeting Add-in for Microsoft Office
Descrição: Microsoft Teams Meeting Add-in for Microsoft Office
ProgID: TeamsAddin.FastConnect
GUID: {19A6E644-14E6-4A60-B8D7-DD20610A871D}
Comportamento do Carregamento: 3
HKLM: 0
Local: C:\Users\Evandro\AppData\Local\Microsoft\TeamsMeetingAddin\1.0.21161.4\x64\Microsoft.Teams.AddinLoader.dll
Tempo de Inicialização (milissegundos): 0

Nome: Outlook Social Connector 2016
Descrição: Connects to social networking sites and provides people, activity, and status information.
ProgID: OscAddin.Connect
GUID: {2163EB1F-3FD9-4212-A41F-81D1F933597F}
Comportamento do Carregamento: 3
HKLM: 1
Local: C:\Program Files\Microsoft Office\root\Office16\SOCIALCONNECTOR.DLL
Tempo de Inicialização (milissegundos): 15

Nome: Microsoft SharePoint Server Colleague Import Add-in
Descrição: The Add-in allows Microsoft SharePoint Server to import colleague suggestions based on your Outlook content
ProgID: ColleagueImport.ColleagueImportAddin
GUID: {EFEF7FDB-0CED-4FB6-B3BB-3C50D39F4120}
Comportamento do Carregamento: 3
HKLM: 0
Local: C:\Program Files\Microsoft Office\root\Office16\ADDINS\ColleagueImport.dll
Tempo de Inicialização (milissegundos): 0

Êxito na solicitação do serviço Web do Exchange GetAppManifests.

The error persists even forcing TLS 1.2 between the 2 servers.

Answer 4

PS:

I created a test database on Exchange Server 2016 CAS (Does not have mailbox) and moved an account to test functionality and the issue persisted.

Then I moved this same account to an Exchange Server 2019 MBX and it worked accessing directly through an Exchange Server 2019 CU11 using my file host by VPN to test the feature works perfectly.

The problem must be in Exchange Server 2016 CU22. I'm testing localhost using 127.0.0.1 webapp.domain.br, the same error on loopback.

Answer 5

interesting that someone is reporting something similar for 2019 CU11:
https://learn.microsoft.com/en-us/answers/questions/606253/exchange-2019-internet-calendar-sharing-doesn39t-w.html

Maybe open a ticket with Microsoft Support?