Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. https://crt.sh/?q=example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
There are dozens of different tools that people can use to get certificates from Let's Encrypt; can you please tell us which particular tutorial you're following?
Here also, it would be helpful to see the exact output—it may be meaningful to someone who's familiar with the software that you're using.
Can you show us what the actual output of the command is?
I'm sure it shouldn't be the version beginning 8e520afa... from the site because that is the demo version that MediaTemple generated to show what it would look like, and the actual signature value that comes out is meant to be different. (MediaTemple is asking you to do this specifically because they don't know what the signature string will be, because only you can create it using your account key, because you're the only one who possesses the account key.)
As an alternative, you could consider using https://zerossl.com/, which has a web interface and concept similar to gethttpsforfree, but automates the process a bit more so that you have fewer tasks to do outside of your web browser while requesting your certificate. You could also consider choosing a hosting provider with better built-in Let's Encrypt support:
You haven’t run the command in the screenshot yet because you haven’t pressed Enter. The entirety of what’s shown in the screenshot is the (long) command itself, rather than the output.