Error loading SSL certificate

I’m trying to make HTTPS work on my Jellyfin server, but no luck. I created a certificate using certbot, then I used:
openssl pkcs12 -export -in /etc/letsencrypt/live/ -inkey /etc/letsencrypt/live/ -out certificate.pfx

I gave it a password.
openssl pkcs12 -info -in certificate.pfx -nokeys

mkdir /var/lib/jellyfin/ssl

cp certificate.pfx /var/lib/jellyfin/ssl/

I made jellyfin the owner of the file and restarted Jellyfin. I added it in Jellyfin’s networking tab and restarted Jellyfin.

Did I do something wrong/forget something?