Mastermind Error – The link you followed has expired.

Hi There, I just bought the mastermind plugin and when i save or delete a feed it gives me error - The link you followed has expired. Here is a video: https://www.loom.com/share/969c4229c01a4870a4a9d5d32723d09c?sid=b653edc5-8235-4583-b709-0a54220eeda6 Kindly let me know what to do. Thanks