Unable to delete tasks posted to different user within MAIL

Unable to delete tasks posted to different user within MAIL

I have 2 tasks that show as belonging to a different user but created by me. I am unable to change the status, edit or delete these tasks as the system comes back to me with an error message " Oops! Something went wrong. Try again later" which of course produces the same result when I do try later...

I have no idea how to clear these tasks from my task list