Users can only upload leaf certificate on portal. They cannot upload root and intermediate certificates. Also, user should not upload self-signed and untrusted certificates.

See below for different types of certificates:

Leaf Certificate : Leaf Certificate will have a full chain of certificates.

Root, Intermediate and Leaf (Main) Certificates

Intermediate Certificate : In Intermediate certificate will have a two chain of certificates.

Root and Intermediate

Root Certificate:-  In root certificate only one chain of certificate.

Root certificate