Setting up VPN that requires a certificate

[SROJR]

Greetings;

Former lurker; first time poster.

Trying to setup a VPN on my 7.0 PLUS Wi-fi only (GT-P6210). I need to install a certificate for access and have setup a password for secure credentials. I've copied the certificate to my SD card. When I try to install the certificate from the SD card option, it says that no certificate file is found.

What I am missing? Can I not set this up? Anyone else got this working? Any and all suggestions greatly appreciated.

Thanks;

Steve