Hello there,
Might check the user has at least list permissions on the files in C:\Windows\System32\Tasks.
Have you already tried navigating to C:\Windows\System32\Tasks to see if it appears there? If it isn't visible, try performing a search within that folder hierarchy. Just to double-check, is it possible that the task name you chose matches a default/built-in Windows task that already exists?
You can also use this script to track the logs https://social.technet.microsoft.com/Forums/windows/en-US/6b9b7ac3-41cd-419e-ac25-c15c45766c8e/scheduled-task-that-any-user-can-run
Hope this resolves your Query !!
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