ASO is one of those profit-driven webhosts who disable cPanel’s built-in AutoSSL feature, that would usually automatically issue and install free SSL certificates for all of your websites and domains. They would rather you pay $40/yr for a commercial certificate.
Unfortunately, for that reason, there’s not really any good solution to using Let’s Encrypt with your shared hosting service. You could try manually issuing Let’s Encrypt certificates for your domain with a tool like ZeroSSL (which you give you the bundle you need), but you would have to repeat the process every 60-90 days due to certificate expiration. It’s not a good solution.
Other choices include paying ASO (or another vendor) for a commercial certificate, or changing to one of many web hosts that provide free SSL.
Another approach, if you are technically minded and have SSH access to your cPanel account, would be to try to setup something like acme.sh: https://github.com/Neilpang/acme.sh/wiki/Simple-guide-to-add-TLS-cert-to-cpanel . But it’s not always possible, given the restrictions some hosts place on their cPanel services.