For CA Bundle use chain.pem. If that doesn't work, for CA Bundle use only the first certificate in chain.pem. If that doesn't work, come back and I'll guide you further.
If it complains about needing to include the root certificate in the CA Bundle, for the CA Bundle use the first certificate in chain.pem followed by this certificate:
In order to install your SSL Certificate you will also need the SSL Certificate of the Certificate Authority (i.e the CA bundle). The CA bundle contains root and intermediate certificates of the CA```
However, we do like scripting and we really hate manual certificate installation
@alento Note that your provider has some silly requirements. At least, the root certificate isn't really necessary and only increases the data required for the TLS handshake and thus a little bit slower. They must have their reasons I don't know if it are good ones though
I think they're just using the root certificate to verify the intermediate certificate. I don't think they're actually serving the root certificate. I could be wrong, but that's the pattern I've seen with some other hosting providers.