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Exchange 2016: after installation of CU 18 attachments from shared mailbox can't be opened in OWA

Christoph 46 Reputation points
2020-09-30T10:31:23.44+00:00

Hi,

we installed last Thursday CU 18 on a single Exchange 2016. After that we recognized that attachment from shared mailboxes can't be opened anymore. This affects all attachments, download and preview. The problem seems to be that the URL for the attachment ist wrong. When we try to download an attchment a new windows is opened and we're redircted to a url in this format (original domain name is replaced):

"https://outlook.office365.com/owa/temp-test@domain-name.de/service.svc/s/GetAttachmentDownloadToken?redirect=%2fowa%2ftemp-test%40domain-name.de%2fservice.svc%2fs%2fGetFileAttachment%3fid%3dAAMkADVjYTJlNmVhLWU5YWUtNDExNC04YmI5LTNkNDI1NzU0YTRhZQBGAAAAAACFeKz%252b7LiwTJTGaiFKmoEUBwDgWBbEnQXzT5ipyGwAVbfZAAAAAAEMAADgWBbEnQXzT5ipyGwAVbfZAAAAAAk3AAABEgAQAHTIfMMNYkBEk%252bb%252f1UJcNZo%253d%26X-OWA-CANARY%3dji4zp9VACUGzxzvHkAjNH0AOjQZUZNgIt7lknLLRBv1JieCvW96de5oLgPWmV6rJSNOZafAG8fU.%26isDocumentPreview%3dFalse

I do not understand why this request is getting redirected to office365.com. We do not have an hybrid enviroment or anything like that. "Normal" user accounts does not have any problems. if we forward the affected e-mail from the shared mailbox to a real person, attachment can be opened. Event logs or similar do not show any related anomalies. Any ideas whats going on or how to fix this?

btw, problem exists only in OWA, the same attachment can be opened in Outlook without any problems. The problem also exists with a new shared mailbox.

kind regards Christoph

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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Accepted answer
  1. David 91 Reputation points
    2020-10-14T09:57:17.057+00:00

    Hi everyone,

    Guess no one found a solution so far and we need a fix from MS?
    We have update to CU 18, same problem. But we do not have the recent updates installed from yesterday patch day.

    One workaround we discovered so far.
    Instead of "Open another mailbox..." you can access the shared mailbox with "Add shared folder..." instead.
    We run a DAG Exchange 2016 cluster on windows server 2012 R2 server.

    3 people found this answer helpful.

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  1. Christoph 46 Reputation points
    2020-10-01T06:03:10.073+00:00

    Hi,

    yes, agree with you thinking it's a bug. Unfortunately there's still no reply from MS tech support.

    0 comments
  2. Christoph 46 Reputation points
    2020-10-01T07:24:27.583+00:00

    btw, found hints that is really a general bug with CU 18

    https://www.frankysweb.de/exchange-server-neues-cu-verfuegbar-september-2020/ -> look at the comments (german only)

  3. Austin Mathis 11 Reputation points
    2020-10-04T15:41:12.887+00:00

    I would like to echo @Christoph experience. We applied CU18 to our Exchange 2016 environment and are experiencing exactly the same problem... verbatim! Single instance, on-prem, no hybrid configuration, shared mailbox attachments being opened in OWA are redirected to office365.com, instead of our external URL.

    Glad to find it's not "just us" - and I'll be following this thread and keeping an eye/ear open for a solution.

    Hopefully we do not have to wait until the next CU to get this resolved.

  4. Christoph 46 Reputation points
    2020-10-04T16:04:33.347+00:00

    Hi guys,

    we opened a support ticket and after a remote session we got the feedback that it‘s a known bug. No fix until yet. Will let you know if there‘s a fix.