Error when saving Unbound Blacklist

[mejobloggs]

Hi guys, new to OPNsense, forgive my ignorance about anything

When I add an Unbound blacklist and click Apply, it says "Error reloading unbound"

The log says:

"[60481:0] notice: failed connection from 127.0.0.1 port 8564"
"[60481:0] error: remote control failed ssl crypto error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate"


I also notice when I log into the Admin page (192.168.1.1), Firefox gives an SSL warning "Firefox detected a potential security threat". Not sure if that's related?

How can I solve this?