Today I ran into a situation where one of the SharePoint Powers users got the message when updating a SharePoint Task Status or completing a workflow assigned to ..
Task update was not accepted.
Also the user received an email below:
I started to investigate the cause of this unusual behaviour and one thing that came to my mind was to check whether the user is a vaild user or any of his permissions changed. Everything looks good and all the permissions were retained as defined.
After a bit of search I was able to figure out that the User who logged in has a change in the AD account due to various reasons. They changed the User account in AD, created a new account and tied it to the same email account. We use Windows authentication for Sharepoint.
After adding the respective user’s new account to the assigned to task, the user was able to update the Sharepoint tasks assigned to him.
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