Task removal of the backup archive never finish and can't cancel

Hello,
i have a problem with two task to remove backup archive on centralised storage.
My tasks have launched summer for 25 days and are stuck at 0% and 1%. If I click stop he asks me a confirmation but nothing is happening. How to delete these tasks? The storage location has since been removed and is no longer accessible. I have restart the serveur but the tasks are still in the same blocking.

I use acronis backup and recovery 10 (10.0.13762)

Thanks for your reply