If you usually execute the apt update command from the terminal and you usually add custom apt sources you might face an error like the following:

E: The repository 'https://dl.bintray.com/resin-io/debian stable Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.

Basically the repository https://dl.bintray.com/resin-io/debian it’s no longer available.

How to fix the error

In order to fix it we might try to find the new repository but in my case it was used to install an application that I’m no longer using it so I’d rather remove it.

To do so I opened the source.list file with vim and root permissions:

sudo vim apt/sources.list

I searched the line where I had that broken repository:

deb https://dl.bintray.com/resin-io/debian stable etcher

And I delete it.

Then remember to save it clicking ESC and then typing :wq.

If you try again with an apt update you shouldn’t get that error anymore.