Please read: docs3.regularlabs.com/sourcerer/the-basi...tyles-and-javascript

If you want to add scripts to every page, you will need to make sure the Sourcerer code gets placed on every page. You could do that by placing it in a module that is assigned to all pages.

Or see if your template provides a way to add custom scripts and styles. Then you do not need Sourcerer for this.

Make sure the editor has not added a link to the URL. So remove any HTML tags inside the {source} tag.

If you can't get it to work:
Can you give me (super) admin and (s)ftp access so I can take a look?
And tell me where you have placed these {source} tags...

Well, you NEED to show the module, otherwise the content containing the code will not be placed on the page.
You can't just place the {source} tags in some random content and expect it to work. It needs to be in content that is displayed on the frontend.

You can assign a custom module to a position that doesn't show the module as a block (depending on your template), and set the module title to not show.

I couldn't log in via the admin credentials.
But make sure the 'Prepare Content' option in the module is switched on.

This is also mentioned ion the documentation:
docs3.regularlabs.com/sourcerer/the-basi...r-files-quick-syntax

You probably have the Page Cache system plugin enabled. That caches the entire page including all modules.
You might not want that plugin enabled.

Read for more on caching here: www.joomlabeginner.com/blog/tutorials/81...able-cache-in-joomla