I have tried to find the answer to this but I couldn't find an answer...
How do I check if my SSL Certificate is using SHA1 or SHA2?
Reason I ask is because it might have to do with the certificate not loading on Mozilla Browers....
Any ideas? Can I check through cPanel?
You can check by visiting the site in your browser and viewing the certificate that the browser received. The details of how to do that can vary from browser to browser, but generally if you click or right-click on the lock icon, there should be an option to view the certificate details.
In the list of certificate fields, look for one called "Certificate Signature Algorithm". (For StackOverflow's certificate, its value is "PKCS #1 SHA-1 With RSA Encryption".)