Schools or workplaces block the soundcloud.com domain directly.
Even if the link works, the proxy server has limited bandwidth. Most "66 links" use overloaded servers in foreign countries. You will likely experience: soundcloud unblocked 66 link
The term "Unblocked 66" typically refers to websites hosted on the platform (which often have URLs ending in sites.google.com or similar subdomains). Schools or workplaces block the soundcloud
: Many third-party proxies and unverified platforms can contain malware, phishing traps, or malicious ads. or malicious ads.