On September 30, 2021, the expiration of one of the root certificates called "IdenTrust DST Root CA X3" took place. This root certificate was used by the Let's Encrypt Certificate Authority (CA).
From this day on, a new root certificate called "ISRG Root X1" comes into play. This root certificate was issued back in 2015 and all modern devices trust this certificate because they include ISRG Root X1 in their list of root certificates.
The "ISRG Root X1" was added to the list of root certificates in macOS 10.12.1 in October 2016, but older versions of the OS don't have this certificate installed.
Convertio uses Let's Encrypt certificates on many internal resources, so you may have issues uploading or downloading files if you are using an outdated OS version.
There are currently 2 ways to use Convertio with the legacy macOS:
- Install the "ISRG Root X1" certificate in the list of trusted certificates manually, following the instructions below.
- Use the Firefox Browser (You need to download ESR (Extended Support Release) version) as it has its own repository of trusted certificates and ignores the system repository. Direct download link: Firefox ESR for OS X
How to install the "ISRG Root X1" certificate on OS X El Captain?
- Download the ISRG Root X1 certificate file from http://x1.i.lencr.org/
- Open the Keychain Access app and drag this file into the System folder of that app.
- Find the ISRG Root X1 certificate in the System and double click on it, open the Trust menu, and change "Use System Defaults" to "Always Trust", then close that and enter your password to confirm the change (if prompted).
- That's all. You should now be able to use Convertio and many other websites without interruption.
Let's Encrypt is used by over 260 million websites, and you won't be able to browse all of them in Google Chrome or Safari unless you upgrade to macOS 10.12.1+, or add the root certificate into the list of trusted certificates manually.
OS X El Capitan was released 6 years ago and has not been receiving security updates for 3 years, so consider upgrading to macOS 10.12.1 or later (Sierra, High Sierra, Mojave, Catalina, Big Sur, Monterey).