unable to upload SSL cert in Appcenter on premise

Hi guys,

I’m now building an on premise appcenter and got stuck at this page (see attached image - error encountered). Just so you know, For SSL Cer File field, I uploaded the cert granted by an internal CA. For SSL Key file field, I uploaded the private key generated upon creating the CSR and for  SSL CA Certificate bundle field, I uploaded the root cert of the internal CA. I used 2048 bit length in creating the CSR.

Upon uploading the said files, I got this error msg (See attached). I have also attached the files I uploaded (cert files.zip)

Anyone here who can shed light on this?

Regards,

Mark