Thanks @fausp for pointing that one out.
I can reproduce the error.
I think it’s due to the Windows line breaks in the certificate/key file created by the Windows CA and I think it’s a bug (and changed the topic category).
I converted (save as) a certificate and a key using Windows line breaks using gedit and got the same error on upload.
The only strange thing is that it worked for the older certificates…
You could try to convert the certificate and the key to Unix line breaks using Notepad++ and check if the upload works.
EDIT:
It seems to be another issue. I tried a cert using Unix line breaks and got the same error so I need to recheck…
If NS is doing anything important on the basis of the Subject: field, that’s very bad practice, as that field’s become all but meaningless in recent years.
Then the domain is extracted out of the subject.
I checked a certificate from CyberGhost and the CN was just a bunch of letters instead of a domain. As far as I can see it’s just used for the redis key name so as long as it’s not empty it shouldn’t matter.