Content Security Policy: The page's settings blocked the loading of a resource

Question

You have said you can only load scripts from your own site (self). You have then tried to load a script from another site (www.google.com) and, because you've restricted this, you can't. That's the whole point of Content Security Policy (CSP).

You can change your first line to:

<meta http-equiv="Content-Security-Policy" content="default-src *; style-src 'self' 'unsafe-inline'; script-src 'self' 'unsafe-inline' 'unsafe-eval' http://www.google.com">

Or, alternatively, it may be worth removing that line completely until you find out more about CSP. Your current CSP is pretty lax anyway (allowing unsafe-inline, unsafe-eval and a default-src of *), so it is probably not adding too much value, to be honest.

With my ASP.NET Core Angular project running in Visual Studio 2019, sometimes I get this error message in the Firefox console:

Content Security Policy: The page’s settings blocked the loading of a resource at inline (“default-src”).

In Chrome, the error message is instead:

Failed to load resource: the server responded with a status of 404 ()

In my case it had nothing to do with my Content Security Policy, but instead was simply the result of a TypeScript error on my part.

Check your IDE output window for a TypeScript error, like:

> ERROR in src/app/shared/models/person.model.ts(8,20): error TS2304: Cannot find name 'bool'.
>
> i ｢wdm｣: Failed to compile.

_{Note: Since this question is the first result on Google for this error message.}

I had a similar error type. First, I tried to add the meta tags in the code, but it didn't work.

I found out that on the nginx web server you may have a security setting that may block external code to run:

# Security directives
server_tokens off;
add_header X-Frame-Options SAMEORIGIN;
add_header X-Content-Type-Options nosniff;
add_header X-XSS-Protection "1; mode=block";
add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'  https://ajax.googleapis.com  https://ssl.google-analytics.com https://assets.zendesk.com https://connect.facebook.net; img-src 'self' https://ssl.google-analytics.com https://s-static.ak.facebook.com https://assets.zendesk.com; style-src 'self' 'unsafe-inline' https://assets.zendesk.com; font-src 'self' https://fonts.gstatic.com  https://themes.googleusercontent.com; frame-src https://player.vimeo.com https://assets.zendesk.com https://www.facebook.com https://s-static.ak.facebook.com https://tautt.zendesk.com; object-src 'none'";

Check the Content-Security-Policy. You may need to add the source reference.

I managed to allow all my requisite sites with this header:

header("Content-Security-Policy: default-src *; style-src 'self' 'unsafe-inline'; font-src 'self' data:; script-src 'self' 'unsafe-inline' 'unsafe-eval' stackexchange.com");