The ltng:allowGuestAccess interface is only usable in orgs that have Communities enabled, and your Lightning Out app is associated with all community endpoints that you’ve defined in your org.
Lightning Out Lightning Components for Visualforce
<aura:application access="GLOBAL" extends="ltng:outApp" implements="ltng:allowGuestAccess"> <aura:dependency resource="c:storeLocatorMain"/> </aura:application>
<script src="https://yourCommunityDomain/communityURL/lightning/lightning.out.js"></script>
For example, https://universalcontainers.force.com/ourstores/lightning/lightning.out.js
Finally, add the JavaScript code to load and activate your Lightning app. This code is standard Lightning Out, with the important addition that you must use one of your org’s community URLs for the endpoint. The endpoint URL takes the form https://yourCommunityDomain/communityURL/. The relevant line is emphasized in the following sample.
<script> $Lightning.use("c:locatorApp", // name of the Lightning app function() { // Callback once framework and app loaded $Lightning.createComponent( "c:storeLocatorMain", // top-level component of your app { }, // attributes to set on the component when created "lightningLocator", // the DOM location to insert the component function(cmp) { // callback when component is created and active on the page } ); }, 'https://universalcontainers.force.com/ourstores/' // Community endpoint ); </script>