If you changed the passkey and the old one is no longer valid. so what you need to do, on all of your torrents in your client, is to update the Tracker URL from the old passkey to the new and active. This is Unique to you, so don't share this with anyone.

If you don't know how to update the Tracker url in qbit client or don't feel comfortable doing so, your other option is to delete the offending torrents but not their data (important!!) and download your snatched torrents again. Since the data is already present, this will not affect your download/ratio stats, but the newly downloaded ones will automatically have the correct Tracker URL.