Unable to verify the first certificate

18 May 2023 | Developer Corner

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Sometimes you may see a diagnostic with the message 'Unable to verify the first certificate'. This issue will appear under the Links category within a Sitemorse Report, under diagnostic section 'url/fetch/exception'.

The problem is a misconfiguration of the SSL certificates on the web server. Almost all Certificate Authorities these days sign web server certificates with what is known as an "Intermediate Certificate". It is very important that the web server is configured to send this Intermediate Certificate along with the web server certificate. Your Certificate Authority will provide you with instructions on how to do this.

As a quick check that the certificates on your web server have been installed correctly, as well as a useful check of the rest of your server's SSL configuration, we recommend using the following free tool:

(This tool will show the warning message "This server's certificate chain is incomplete" in the Summary section at the top of its output if your Intermediate Certificate is missing.)