If you have installed an SSL certificate on InfinityFree, you may want to use an SSL Checker tool to verify your SSL certificate was installed correctly. However, when doing so, you see an error like this:
The certificate is not trusted in all web browsers. You may need to install an Intermediate/chain certificate to link it to a trusted root certificate. Learn more about this error. The fastest way to fix this problem is to contact your SSL provider.
What does this warning mean for your site
This warning can be safely ignored. While it’s true that some browsers may not accept your SSL certificate, almost all modern browsers on all devices do. You can be sure that 99% of all devices that have been updated in the last five years can see your site without any problems.
How can I install this intermediate certificate
Installing intermediate certificates / CA Chains is not supported on free hosting. This feature is only available on premium hosting.
What does this “intermediate certificate” mean
When you receive an SSL certificate, you generally get another file with it called something like the “CA Chain”, “Certificate Chain” or “Intermediate Certificates”. In the best SSL installation, you install this CA chain along with your SSL certificate.
Your computer and/or browser has a list of SSL certificate providers they trust, and your SSL certificate has a reference as to which SSL provider created that certificate. However, the reference in your SSL certificate is usually not linked directly to the trusted providers in your browser. For security, SSL certificate providers put an extra certificate (or multiple) in between your domain certificate and their browser/OS certificate.
In the past, installing this extra certificate was required for an SSL certificate to be accepted. But most modern browsers keep track of these intermediate certifiacates, so individual sites don’t need to provide them. Additionally, modern certificates have embedded references as to which intermediate certificate created them, which browsers can use to fetch the intermediate certificate themselves.
All in all, modern browsers work just fine without the intermediate certificate.