Firefox: certificate can’t be installed [closed]

Question

I would like to run an https C++ server from this source code.

I have followed up this website to generate the certificate:

openssl genrsa -des3 -out server.key 1024
openssl req -new -key server.key -out server.csr
cp server.key server.key.org
openssl rsa -in server.key.org -out server.key
openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt

which led to creation of four files:

server.crt
server.csr
server.key
server.key.org

Then, in my firefox browser, I go to preferences/advanced:

about:preferences#advanced

Then view certificate, your certificates, import.

But at the end, I face with an error and nothing happens:

This personal certificate can’t be installed because you do not own the corresponding private key which was created when the certificate was requested.

All necessary file including server.key are there.

What is the problem?

What should I do?

Answer 1

It looks like that Firefox (and Chrome too) can only import key and cert together if they are inside a PKCS#12 file but not when they are in a PEM format. To create such a file from the created certificates:

openssl pkcs12 -export -in server.crt -inkey server.key -out server.p12

Then import the server.p12 file in Firefox.