Firefox – Why Firefox alert me about HTTPs “Untrusted” Connection on Positivessl – Comodo certificate


For my new startUp I got a SSL certificate from I did all the painful process and finally I was able to implement it on my AWS server (I'm running MEAN Stack). Now when someone visit my website using Firefox the got this error:

Technical Details

Invalid security certificate.

The certificate is not trusted because no issuer chain was provided.
(Error code: sec_error_unknown_issuer)

But obviously I don't want my users to receive that warning.

I thought that maybe the server was delivering some file by the regular http and I couldn't find any non-https content, so I imagine I'm ok about that issue (maybe not)

This is my first time using a SSL certificate and maybe I'm doing it wrong. Please if you can help me out will be great. Thanks

Here is the image:

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Best Answer

Although you did install a SSL certificate, you did not include any additional certificates that are necessary to build a trust path. See

About the trust path, the SSL client has some root certificates that are stored. When you buy a certificate C from some CA, they might use some intermediate certficate (let's call this B) that is signed by the root CA A. If you only provide the certificate C to the client, then they will not be able to establish a trust path from A to C. To fix this, append the certificate B to your certificate C.

The exact details depend on the SSL server that you are using, consult their documentation for the specifics.