video apps MKV files is useless on ubuntu 21.04 and linux mint 20.1

Hi i have issue

Its give usless video performance with nvidia 460 on both system so its need to be fixed.

Fix your email: smtp.gnome.org rejected your message to the following email addresses:

gnome-multimedia@gnome.org The address you sent your message to wasn't found at the destination domain. It might be misspelled or it might not exist. Try to fix the problem by doing one or more of the following:

Send the message again, but before you do, delete and retype the address. If your email program automatically suggests an address to use, don't select it.
Clear the recipient AutoComplete cache in your email program by following the steps in this article: Status code 5.1.1. Then resend the message, but before you do, be sure to delete and retype the address.
Contact the recipient by some other means (by phone, for example) to confirm you're using the right address. Ask them if they've set up an email forwarding rule that could be forwarding your message to an incorrect address.![capfpffjpcomdekk](/uploads/20487317dee11564e19b285402b6c800/capfpffjpcomdekk.png)

Issue make video to be not readable and look very buggy out its better to remove this app and use videolan or other app to video.