Error -19761 when sending mail (The send or update operation could not be performed because the change key passed...)

Anonymous
2016-10-04T16:13:47+00:00

I’m having a problem with one user in our system. Details are as follows:

Platform: OS X 10.10.5

Outlook version: Outlook for Mac 2016 (15.26.1)

Problem: Randomly (about 5-10 times through the work day), when the user sends an email, they get an error in Outlook for Mac, the message is not sent, and the message is put in their Drafts mailbox. The error that is displays is as follows:

The send or update operation could not be performed because the change key passed in the request does not match the current change key for the item., Cannot submit message.SaveStatus: IrresolvableConflict

PropertyConflicts: Mail could not be sent. The message has been moved to your Drafts folder.

Account name: "XXX"

Error: -19761

They then open the message from their Drafts folder and attempt to resend it. It then sends without issue.

Some additional notes:

  • The error started happening 2 days ago—no changes were made to the user’s machine prior to the error appearing.
  • The error happens when sending to both internal and external contacts.
  • The error only happens when using Outlook for Mac desktop client (the issue does not happen when sending mail via OWA or iPhone, etc.)
  • We have updated Outlook for Mac to the latest available version (15.26.1).
  • We have deleted/re-added the account in Outlook.
  • We have uninstalled/reinstalled the Office 2016 package on the computer.

Any advice would be appreciated.

Thanks,

Kristin.

Outlook | MacOS | Legacy Outlook for Mac | For business

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  1. Anonymous
    2017-08-29T19:38:03+00:00

    One of our products also experiences this error very often when creating/updating calendar events against the Office 365 REST API. Create events get this issue on occasion. Updates to existing events, however, experience this error very often.

    I posted a question about the error on StackOverflow: https://stackoverflow.com/questions/45502093/change-key-error-when-creating-calendar-events-via-office-365-v2-rest-api

    We are using the 2.0 OutlookServices library to interact with the REST API.

    We've searched for a cause on our end, but have been unsuccessful. Is it possible there is still an underlying issue in Office 365? If not, any guidance would be wonderful.

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  2. Anonymous
    2017-12-14T16:26:20+00:00

    I am experiencing the same issue with one of my Mac users, is there a solid solution for this? 

    Been looking for an answer but I can find a definite solution for this.

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