You might be trying to install SSL on a temporary domain like box223.temp.domains/~wpencryption which is not possible. Please change your temporary domain to a real domain name like wpencryption.com and then proceed with with SSL installation process.
You can easily change from temporary domain to real domain following below instructions:
https://www.bluehost.com/help/article/using-your-temporary-url-with-wordpress#changing-from-temp
