Legacy SSL Proxying
Version of Charles prior to v3.10 used a single SSL Root Certificate. You can still download the legacy certificate bundle here or the certificate itself here (for installing on mobile devices). Note that these certificates will not work on Charles v3.10.
If you are running Charles v3.10 or later, please go to Charles and consult the SSL Proxying submenu in the Help menu, for instructions on installing your new Charles Root Certificate.
You can also check the documentation on SSL Certificates for instructions for installing your Charles Root Certificate on various devices.