As of this writing, a search for "All That Heaven Allows" on archive.org typically yields several results:

If you are a casual viewer who wants to see what the fuss is about, go ahead and stream the Archive version. It will move you. But if you fall in love with Cary and Ron (and you will), do the right thing: buy the Criterion disc, rent the HD stream, or request it from your library. The film deserves to be seen in all its Technicolor glory.

The provides free access to Douglas Sirk's 1955 cinematic masterpiece, All That Heaven Allows

Happy watching, and enjoy this slice of Hollywood's Golden Age!

Even though the legality of streaming All That Heaven Allows on archive.org is questionable, the existence of such uploads serves a higher cultural purpose. Thousands of films—especially mid-century melodramas—are not available on any streaming service in certain countries. They are locked in rights disputes, or the rights holders simply ignore them because they are not "profitable."

(Search for “All That Heaven Allows 1955” – look for the Sirk title card and the shimmering autumn leaves. And bring tissues.)