having trouble to upload SSL certificate

i am done with everything and completed all the steps to install ssl certificate , and now when i am trying to upload the certificate it doesn’t let me install it, all the time it says the same thing “If you have an existing key / certificate for a domain, enter it in the correct fields below, and click the ‘Upload’ button.
If you are needing a new certificate, use the ‘Generate Key / CSR’ button, this will then generate a new CSR and private key, you then supply these to the ssl signer who will then issue a certificate that you must upload in the Certificate box to complete the SSL activation.”
please help me out to fix this problem, every detail i put in certificate and private key all are correct but still same problem

Which SSL vendor did you use?

@Admin said:
Which SSL vendor did you use?

I’m having same issue on my infinity free hosting account. I have just got a new certificate Comodo Positive SSL…Please help as the same window reappears after pasting Certificate text and clicking “Upload Certificate” button.