The button to delete / disconnect certificates from user entries is missing. So it is not possible to delete invalid certificates as long as they are connected to a user record.
Nothing is linked really. It's only a common name match.
Cheers,
Franco
If I try to remove a certificate which is connected to a user, I get the error message in the screenshot. If I remove the the user, I'm able to delete the certificates. But that's of course not what I want ;-) The "delete certificate" button in the user management is missing in 24.7. It was there in 24.1.
Feel free to open a bug report. It's difficult to support a moving goalpost here.
Cheers,
Franco