Git fatal: protocol 'https' is not supported

I am going through Github's forking guide: https://guides.github.com/activities/forking/ and I am trying to clone the repository onto my computer. However, running the command:

$ git clone https://github.com/./Spoon-Knife.git
Cloning into 'Spoon-Knife'...
fatal: protocol 'https' is not supported

Also tried with SSH:

$ git clone git@github.com:./Spoon-Knife.git
Cloning into 'Spoon-Knife'...
Warning: Permanently added the RSA host key for IP address '.' to the list of known hosts.
git@github.com: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Do I need to change some configuration setting on my computer or is this a problem with GitHub?

Edit: I have replaced my username and IP address with "."

Solution

The problem is probably this:

You tried to paste it using CTRL + V before and it didn't work,
so you went ahead and pasted it with classic Right Click.
Sadly, whenever you enter CTRL + V on terminal it adds a hidden ^? (at least on my machine it is encoded like that) character that only appears after you backspace (go ahead and try it on git bash).

So your link becomes ^?https://... which is invalid.