You would face the root certificate not trusted error is the Securly SSL certificate is not installed on your macOS X.
To stop receiving the error you would, therefore, need to install the SSL certificate.
- Download the Securly certificate CRT file. (securly_ca_2034.crt)
- Navigate to Finder > Applications > Utilities > Keychain Access
- Select ‘System’ in the left-hand column.
- Open ‘File > Import Items’ and import the certificate file into the ‘System’ keychain.
- Alternatively, you can automate the installation process via MDM by downloading the executable file at the end of this article.