apt update "does not have a Release file"

Question

I'm trying to fix this issue when running sudo apt update:

E: The repository 'https://download.docker.com/linux/ubuntu loki Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

I tried adding the correct repository:

sudo add-apt-repository    "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
   xenial \
   stable"

Also tried searching for the "loki" keyword and replace to "xenial", no luck:

lucaswxp@imhuman:/etc/apt/sources.list.d$ cat * | grep "loki"
> empty result

Any idea how to get apt update to work again?

Answer 1

So, I was looking in the wrong path. The file I needed to edit was /etc/apt/sources.list. I just replaced loki to xenial and it worked.