Did you forgot to mark this CheckBox during Certificate Import?
Luckily iSECPartners has created a Jailbreak software for this task.
Software: https://github.com/iSECPartners/jailbreak
...\jailbreak-master\binaries>jbstore64.bat -s "SYSTEM" -o outputFileName.pfx -n "certificateName" -p "password"
Default password for exported certificate (if not provided as -p parameter): "password"
