SSL Certificate import error

Hello,
I'm using I-MSCP 1.3.0 (Debian Jessie 8.5 - fresh install) and I'm trying to enable SSL for a domain created.
I've followed this tutorial to the letter:

https://jamielinux.com/docs/op…thority/introduction.html

I've setup my Root CA, Intermediate CA, Chain Certificate and a cert for my domain (for test purposes it's koy.org). Of course I'm using the appropriate dialog in I-MSCP Panel to implement these changes, but each time I try to import an SSL cert for my domain I get an error message saying: At least one intermediate certificate is invalid or missing.

Could someone please have a look at my issue and hopefully offer some advice how to fix it.
I'm attaching all the relevant certs I've created so you can see what they look like.
All these certs were created with OpenSSL on the newest possible Debian Jessie distro.

Please advice and thank you in advance,
Martini

It seems extremely unlikely IMSCP would have a root certification authority list, and even if was so I think it would be possible to add my own root CA to it. Besides I wouldn't want to be dependent on an outside SSL authority.
I wonder if somewhere in the process there is an error I've made that make's IMSCP flip like that, but there probably is a way to fix it, I just don't know what it is (at least for now).
Please advice.