Securing printers with CA certificates

[CH_in_SWMO]

I am having trouble securing my company's networked printers using CA certificates. I create a certificate request from a printer and try to upload it to my subordinate CA. The CA kicks it back saying that the request is lacking needed information:

     "request contains no certificate template information. 0x80094801"

I can upload the request to the Root CA server, but when I pull down the approved certificate and apply it to the printer, my web browsers (Chrome & Edge) say there is a problem with the certificate:  NET::ERR_CERT_COMMON_NAME_INVALID. I get this on an M401n and an M402dn. 

Does anyone have any insight concerning implementing CA certificates on HP printers in order to create a secure HTTPS connection?

[Repairatrooper]

Are you trying to use the same certificate on multiple printers? I believe you need to generate and apply a cert for each device. If you have a large number of devices to support HP Security Manager automates this entire process for you. 

[CH_in_SWMO]

For both printers that I am testing, I can directly install the CA's certificate and that will work fine.

But then I need to create a certificate request originating from each printer which  I then upload to the CA server. Then I can issue each certificate on the CA server and download it to the printer.  I was able to get past the template error using a "CertReq" command which makes me specify which template to use. I submitted the request and it created a new certificate. I installed the certificate to the printer and it was successful. The only issue I still have is that the web browser still shows an error when I re-open the printer's web interface.

That error is: NET::ERR_CERT_COMMON_NAME_INVALID