Hey Jungle, I`ll help you out a little bit :), A Source key is an HTML-Code, not some regular words. So you need to find the HTML-Code for the login error you get.
This is what you need to do:
1. Log in on the website with an invalid email:pass, so you`ll get an error when you hit the login button.
The error on your website is: "Email ou password incorrecto". That's not a Source key, but a Header key.
2. Search for the HTML code, so right-click on the error and then inspect(On google chrome).
3. You will see a popup on the right side of your screen, and a blue highlighted text. So Right-Click on the blue highlighted code, and select: "Edit as HTML".
4. Copy everything in the HTML-Box, and paste it into Source failure keys, so paste this: "<span class="error" id="errorMessage">Email ou password incorrecto. </span>" With the Add(Basic) button.
5. Right now, login with a valid account, and search for the logout button.
6. Right-click on the logout button and click on inspect.
7. Rightclick on the blue highlighted text, and then Edit as HTML.
8. Copy everything in the HTML-box, and paste it into Source success keys.
RIGHT NOW IT NEEDS TO WORK!
If you can`t understand some parts, I am Dutch, so I am not the best at English!
If you got questions about this? Contact me on Discord: Plakt0ets#5137