Delete Activity - on 2.13 doesn't work

Hi, I have have 2.13 Opigno version. When I try to remove an activity as a Admin, I get the pop-up window confirmation and when I confirm > nothing happen..! Checking the console, I have the bellow error message : ok: false status: 500 statusText: "500 Service unavailable (with message)" type: 2 url: "" _body: "↵The website encountered an unexpected error. Please try again later." Thanks for your support,