Secure Firewall Login with Certificate

Hello,

I am trying to secure my management logins with an SSL Cert.

I generated a CRT and then downloaded the Cert from GoDaddy. I then imported into system --> certificates --> local cert --> import etc...

Once that was done I then went to system --> settings --> Administrator Settings and chose my new certificate.

This prompted me to lose connection to the firewall. I then reconnected but it doesn't seem to have worked. Have I missed a step?

Also can I use the same cert on other fortinet firewalls?

Thanks,

Glenn