Comparing content of your external certificate with default. Kloxo-MR using format .key and .pem (combine .key and crt).
I see ...
default.key=privatekey
default.crt=crt
default.pem=crt+privatekey
default.ca=intermediate?
Kloxo panel has only 3 Add Upload Files: Key File (.key?), Certificate File (.crt?), Certificate CA File (.ca???)
.key=private key?
.crt=public key send by sslregistor??
.ca=controlkey send by sslregistor??