Securly_SHA-256 Certificate is expiring in 2020. Once it expires, it won't work. Please make sure you install Securly_ca_2034.
Issue: You need to verify the Securly SSL certificate has been installed in Mac OS X
Solution:Navigate, in Finder, to Applications > Utilities > Keychain Access.
- Double-click to open Keychain Access.
- Select the “System” keychain, select Certificates under Category, and look for the *.securly.com SSL certificate.
To install the Securly SSL certificate
- Open Keychain Access>File>Import Items
- Navigate to the location that you saved the Securly SSL certificate file to (you can download the file below)
- Import the "securly_ca_2034.crt" file into the “System” keychain
- Verify the SSL certificates: Issued To "*.securly.com" is installed
Source: Securly