Why am I getting Cloudflare CSP errors and a 403 when opening my pixel-art site?

The important part is the 403 and the message that the account has been blocked. The CSP, WebGL, font, and sandbox messages may be side effects of the security challenge failing rather than proof that your device is infected or that the site has been compromised. Try the site in another browser, on another device, and from a different network such as mobile data. If it works in one combination, that should help identify whether the issue is browser-related, device-related, or tied to your network or account. Since clearing cookies didn’t help, the site owner or its security provider may need to remove the block.

Those logs are mostly diagnostic noise from the challenge page. A browser blocking a blob script because of a Content Security Policy does not automatically mean the script is malicious; it can simply mean the challenge and the page’s security rules are incompatible in your current setup. The WebGL errors are also usually graphics-feature compatibility warnings. Don’t disable browser security settings or enable unsafe eval just to get around it. Test with extensions disabled or in a private window, then contact the website’s support team if the account remains blocked.