ErrorNoRespondingCASInDestinationSiteExchange after moving account from Exchange 2016 to 2019 RRS feed

  • Question

  • We have the below issue with a client, who is moving from Exchange 2016 to 2019.
    We sync calendars using EWS and SOAP calls. IIRC the login is with Basic Authentication in the HTTPS

    Old working configuration:

    • 2 Exchange 2016 servers in one cluster behind a load balancer
    • There is one service acount, an ADUser with a mailbox (let's call it ADUSER), who has been given publishing editor rights to the calendars we need to sync.
    • Our software logs into EWS with the ADUSER credentials and updates the calendars for all other users

    Intermediate configuration:

    • Added: 2 Exchange 2019 servers in one cluster behind a load balancer. New mailbox databases.
    • Moved some user accounts to 2019 for testing (not the ADUSER)
    • The X-AnchorMailbox header was added to the HTTPS requests for the sync to work correctly (we got the ErrorNoRespondingCASInDestinationSiteExchange without that)

    This succesfully syncs accounts on both 2016 and 2019

    Current configuration:

    • The ADUSER was migrated to the 2019 environment

    Now the sync no longer works. The server returns as error in the 'Fault' XML node:

    Exchange Web Services are not currently available for this request because none of the Client Access Servers in the destination site could process the request.

    • This is both when accessing 2019 and 2016 calendars
    • Disabling the load balancer did not help
    • Adding the header X-PreferServerAffinity:"true" did not help
    • FWIW Our SOAP call still have RequestServerVersion Version="Exchange2007_SP1"
    • I have read that 2019 only allows TLS 1.2 connections. We do not specify anything here and let the handshake/OS handle this.

    We are at a loss here.

    What more can we test/reconfigure to try to get this working?
    Tuesday, March 17, 2020 1:06 PM