Then it probably isn’t a root shell.
Do you see anything like “cPanel” when you’re logged into your Afrihost environment?
I’m afraid that with Afrihost things aren’t that easy. At least not as easy as Let’s Encrypt is intended to be used. From their webhosting FAQ:
Are there any extra costs involved in hosting a secure site (i.e. having a SSLcertificate)?
Yes, you’ll need to get a digital certificate from a Certificate Authority such as VeriSign or Thawte. This will be an additional cost over and above your hosting fee. Please contact us if you need to set up yourSSL certificate.
Let’s Encrypt is meant to be automated, i.e., when the lifespan of the certificate is almost over (the certificates are only valid for 90 days), it should be renewed automatically somehow, by the software used to get the certificate in the first place. But when you have to manually get the certificate (which is possible) and have to send it to your hosting provider somehow, that’s very cumbersome.
For example, you could use ZeroSSL to get a certificate. And somehow e-mail it to your hosting provider. But what your hosting provider should do, is enable AutoSSL in their cPanel control panel (if they’re using cPanel anyway). And if they’re not using cPanel, they should enable some other client in their control panel to let you get a Let’s Encrypt certificate with just a single click on a button.