root@my /home/frank/ssl # openssl x509 -noout -modulus -in www.interssl.at.neu.crt | openssl md5
(stdin)= 16ab8bfbfd35a1d1a68123e81318a4df
root@my /home/frank/ssl # openssl rsa -noout -modulus -in www.interssl.at.neu.key | openssl md5
(stdin)= 16ab8bfbfd35a1d1a68123e81318a4df
root@my /home/frank/ssl # openssl req -noout -modulus -in www.interssl.at.neu.csr | openssl md5
(stdin)= 16ab8bfbfd35a1d1a68123e81318a4df
In case the files are not matching each other, you will see different MD5 codes printed out and the files cannot be used together on your server. - You can either go and find the proper private-key/.csr pair that is matching the .crt - OR: re-issue a new certificate that will be matching your private-key/.CSR pair.