Browser does not accept certificate of my own website, even if it is signed by a trusted CA

Browsers should be able to determine if the webserver is really who he says and building up a secure connection to it. Even if there are no errors in the configuration, the webserver starts and the client gets the right certificate at the connection the browser says the connection cannot be trusted and is not secure. The certificate is signed by a trusted CA and the CA certificate is trusted by the browser.
1 answer

How to configure a webserver with certificates

If you want to secure your webserver with ssl (HTTPS) then you have to generate a certificate and get it signed by a trusted CA.
Configure the webserver to use this certificate for the secured site.

If your browser complains about an untrusted connection even it gets the right certificate from the webserver, check if there are intermediate certificates you have to provide too.

If you can't configure your webserver to do this, you can past the intermediate certificate at the beginning of your certificate file (if it's ASCII-Armor) and your browser should recognize it.